What is DDR2 in the computer. How to find out which RAM: DDR, DDR2, DDR3 or DDR4. What kind of RAM to take

There are several common types of memory modules used in modern computers and computers released several years ago, but still working in homes and offices.
For many users, to distinguish them both in appearance and performance is a big problem.
In this article we will consider the main features different modules Memory.

FPM.

FPM (Fast Page Mode) - View dynamic memory.
Its name corresponds to the principle of operation, as the module allows you to quickly access data that are on the same page as the data transmitted during the previous cycle.
These modules were used on most computers with 486 processors and in earlier systems with pentium processors, tentatively in 1995.

Edo

EDO modules (Extended Data Out) appeared in 1995 as a new type of memory for computers with Pentium processors.
This is a modified FPM version.
Unlike its predecessors, EDO begins a sample of the next memory block at the same time when it sends the previous block to the central processor.

SDRAM

SDRAM (Synchronous DRAM) - a view of a memory with random access that works for so much to be synchronized with the frequency of operation of the processor, excluding standby modes.
The chips are divided into two cells of the cells so that during reference to the bit in one block, preparations for accessing a bit in another block should be prepared.

If the time of reference to the first portion of the information was 60 ns, all subsequent intervals managed to cut up to 10 ns.
Since 1996, most Intel chipsets began to maintain this type of memory modules by making it very popular until 2001.

SDRAM can work at a frequency of 133 MHz, which is almost three times faster than FPM and twice as fast as EDO.
Most computers with Pentium and Celeron processors released in 1999 used this particular memory.

DDR.

DDR (DOUBLE DATA RATE) has become an SDRAM development.
This type of memory modules first appeared on the market in 2001.
The main difference between DDR and SDRAM is that instead of doubling clock frequency To speed up the work, these modules transmit data twice in one clock.
Now it is the main standard of memory, but it is already beginning to give up its position DDR2.

DDR2.

DDR2 (Double Data Rate 2) is a newer version of DDR, which theoretically must be twice faster.
For the first time, the memory of DDR2 appeared in 2003, and chipsets supporting it - in mid-2004.

This memory, as well as DDR, transmits two data sets for the clock.
The main difference between DDR2 from DDR is the ability to work at a significantly higher clock frequency, thanks to the improvements in the design.
But the modified scheme of work, which allows to achieve high clock frequencies, at the same time increases the delays when working with memory.

DDR3

DDR3 SDRAM (synchronous dynamic memory with arbitrary access and double data transfer rate, third generation) is the type of RAM used in computing technology As operational and video memory.
Came to change the memory type DDR2 SDRAM.

DDR3 is reduced by 40% energy consumption compared to DDR2 modules, which is due to reduced (1.5 V, compared with 1.8 V for DDR2 and 2.5 V for DDR) the supply of memory cells.
The reduction in supply voltage is achieved due to the use of 90-nm (first, in the future 65-, 50-, 40-nm) technical process in the production of chips and the use of transistors with a dual-gate double gate (which helps to reduce leakage currents).

DIMM modules with DDR3 memory are mechanically not compatible with the same DDR2 memory modules (the key is located elsewhere), so DDR2 cannot be installed in the DDR3 slots (this is done to prevent the erroneous installation of one modules instead of others - these types of memory do not coincide by electrical parameters).

Rambus (RIMM)

Rambus (RIMM) is a type of memory that appeared on the market in 1999.
It is based on the traditional DRAM, but with a fundamentally modified architecture.
The design of the Rambus makes the memory appeal more "reasonable", allowing you to obtain preliminary access to the data, a little unloading the central processor.

The basic idea used in these memory modules is to receive data with small packages, but on a very high clock frequency.
For example, SDRAM can transmit 64 bit information at a frequency of 100 MHz, and Rambus is 16 bits at a frequency of 800 MHz.
These modules were not successful, since Intel had a lot of problems with their introduction.
RDRAM modules appeared in gaming consoles Sony PlayStation 2 and Nintendo 64.

Translation: Vladimir Volodin

Got a question from Alexander Shilina:

My people have such a question, and if I have a ceiling on my mother, 600+ then 667 planks will go? And then with a 600 frequency I did not see at all, I saw only 667 and higher.

To be honest, then the motherboard with the support of memory with the working frequency is not higher than 600 MHz found failed, and the RAM with a frequency of 667 MHz almost disappeared from the sale.

But the motherboards, which in the characteristics declared support for DDR2 667/533/400, but not a word says about DDR2 800, it was possible to find. One of these boards is ASUS P5LD2 on the Intel 945P chipset.

The chipset is old, and, most likely, when a computer with such a motherboard was going to, then no more than 1GB of memory was installed in it, and then only 512MB. However, no one has canceled the desire to increase the performance of the computer by increasing the volume of RAM.

Only here is not in memory stores with the required characteristics of DDR2 667/533/400, and there is only DDR2 800. Is it possible to install it? Does it work?

Can.

To make sure that you will launch the CPU-Z program, which I have already praised when I wrote about that. Only this time will open the SPD tab.

Here is an example for DDR2 PC2-5300, 667 MHz:

DDR2 PC6400, 800 MHz:

But the memory, officially marked as DDR2 PC6400, 800 MHz, but supporting work at a frequency of 1066 MHz:

The most interesting for us in this case is the Frequency stitch in the Timings Table section. Only the frequency value (Frequency) must be multiplied by 2 to get the values \u200b\u200bspecified in the prices and manuals to the mat. fees.

In general, the SPD is a system of profiles, stitched into the RAM, which informs the motherboard via BIOS, at what frequency this plank is capable of working.

And then it can be seen that DDR2 PC2-5300, 667 MHz can work not only at a frequency of 667 MHz, but also at 533 MHz, and even 400 MHz.

The same can be said about DDR2 PC6400, 800 MHz. The absence in the mention plate on the possibility of working at a frequency of 667 MHz is caused, I suppose, save space.

I think that the last plank will earn even at the frequency of 400 MHz. Only here from an economic point of view to buy in this case very strange.

So buy DDR2 PC6400, 800 MHz and boldly install it on the motherboard with only DDR2 667/533/400 support. Everything will work perfectly and even more reliable, because This plank will have a tangible margin of safety, instead of working at the limit. 🙂

comments 28.

Ilya (July 29, 2009, 15:56)

You can install quickly on the board with support for only slow memory - it will simply work on the maximum supported mat. Speed \u200b\u200bpayment (i.e. low).

(July 29, 2009, 16:01)

Ilya, actually wrote about this, only in order not to be unfounded, added several images. 🙂

Anton Young (July 30, 2009, 11:30)

\u003e ASUS P5LD2 on the Intel 945P chipset.
I have such a mother 🙂

\u003e When a computer with such a motherboard was going to, then no more than 1GB of memory was installed in it, and then only 512MB.
I, probably, ebonut. But I have 3GB. I love when a lot of memory.

(July 30, 2009, 13:40)

Anton, Gicks do not count. 🙂
I meant standard configs that lie to people.

Igor (August 27, 2009, 00:56)

In general, one radish confused in this memory. The laptop supports 533 MHz, stood a double bank of 512MB PC4200 worked at 266 MHz. I installed the ETOT PC6400 (800) thought would work for 533 MHz. And it is not so much - 36MHz. In short, the screenshots snapped here: http://komp-kompyuerov.narod.ru/index.html What's what? Or everything is true 400x2 \u003d 800. \u003d) ... hike I have enlightenment later. Then why fool the people with east of themeghellians?

(August 27, 2009, 07:01)

Igor, 800 - this is obviously when the two-channel mode is activated: 2 channels of 400 MHz in the amount are given 800.

In the case of laptops still cunning. This screenshot clearly shows that the maximum frequency (RAM MAX support) is 533MHz. Those. In the case of one strap - 266 MHz.

But it is not worth upset. 🙂 2GB In any case, much better than 512MB, and 800 MHz are not more expensive now than 533.

Igor (August 28, 2009, 09:51)

Well, at least the question with the "Hapan" from the paging is now solved. And then there was a slower not for childish. :)
Well, in short, I could not blame the innovation. The laptop happened to the laptop. (Mothers blood did not shed but ..) By the way, as a result of what happened when I try to open mp3 Windows MP writes that "I could not perform an operation because of the lack of memory." Whether it is not a mockery? :) And the classic player opens fine. And a lot of things are not very good. Well, it already belongs to problems of windows or security. Maybe where is the appropriate topic? Or here in offtopim? Then let's go on the problem globally.

(August 28, 2009, 09:55)
Igor (August 30, 2009, 04:06)

Well, as they say it went such a thing ... uh ... Timelessness. 🙂 at first the total episode; Objects (folders, labels, etc.) as if nails are nails and not moved by any click, stopped working to "insert" the context menu (always inactive), in the error logs, these most errors have not clicked to see the description, when entering accounts, an empty window without Choosing anything, in the Task Manager, the absence of yourself is a favorite on the Table tab and generally loss of administrator rights, a partial or complete xs (Communication when trying to start the application on disk d), processes in the Task Manager instead of +50 left 30+, periodic reboots with a blue screen (quickly pellerying, do not have time to smoke what is happening there), later it was possible to find out the error code
Error code 10000050, parameter1 8F640CEC, parameter2 00000001, parameter3 805B641A, parameter4 00000000.
Error code 10000050, parameter1 C399FF20, parameter2 00000000, parameter3 BF80DD9B, parameter4 00000000.
approximately in such a spirit, when trying to scan to viruses, too, reboot (actually with them and tried to fight for 3 days), reports of the Pokhatnaya file System on C, well, etc. and TP. The main problem was texts with passwords / login to remove. I was already morally ready for rewriting into manual, yes, remembering the disk with Windows safely used the file transfer wizard. (Not so badly smallest as they are in fact \u003d))) why it all started already and not mention, but just after As the manipulation of memory started, there was still a freezing of something, Skandisk, and went to go. I tried and restoring the system to make a mistake and reboot. (now I write in Pad and after each Ctrl + S proposal, because I regularly rebuild the Gadan :(). Everything described was held with Hoham Edishin, the second XP (cropped by Geim Edishin) was also almost never launched at all, complaining of C. with safe regime Also, the intelligent nothing went out. Purchased I pulled up heavy artillery and Acronis True Image Home 11.0 Liked the Logic C. Everything seemed to work normally (although it should not guarantee such a suck in my head :)) And the second axis earned. Exchanged Memory (GoodRam) I think there was a gossible plank. Inserted, it seems fine Everything in PC Wizard 2008 even tested, something showed how my old 4200. Well, okay, I connected to DSL Yes, let's download new clothes. Robust then Akronis was as much as October 2008, albeit with almost all the necessary programs. Well, here I am sitting on the iron friend here ... and Baz. Again the old song. Reboot ... Mother ... Long type there was no. Similar codes, application error log is already damaged. It was hanging something (again by my memory :), Scandisk picked something there. True, this time on the folder disk it was not the same where such 000 at the end.
So I returned again after the rebut. :) Some kind of crap wanted on the Internet (it is disabled), forbade in the Domato. Then he went into him to see more about what it was, clicked in the journal ... The window of errors and reboot. After the message Savedump.exe error and now there is no record of this event. Something I really do not know what to think. We can really do any virus. Maybe what a stzuka (no longer holding back) in MRR prescribed? Well, there is an Acronis (restoration recovery). True launching it with the choice of F11 (recovery) 2-3 times yesterday was, and even now highlights MBR ERROR 2. Can there be what lies here? In short, everything is no strength. I lay out and go to bed. Tomorrow (today already) I will restore Aroneis again and see how it will develop with the old memory. Shl to the way and the mouse has adjusted the on the day before with the double click button ... Maybe what is there? \u003d)))))) Zyy shudded, I will not break away. Overloaded again. And again I climbed into there is no synchronizer small-scale. Something like this. I could not go to the flap to go in rebuilding, spit put his RAM. It seems that some minutes holds. :) That memory was such a hot ... although the laptop after all.

Igor (August 30, 2009, 04:09)

What am I Tuban's unique content? :) True, paragraphs did not exit ...
The peeper test turned out at the same time. :))

(August 30, 2009, 08:33)

Igor, it is no longer like memory, especially, given its replacement.
It looks like:

1. Virus. It would be nice to boot from any Live CD and check "Dr.Web Cureit!", Fortunately, the installation is not needed.

2. But even more it looks like a death hard disk. Check again, it is better to run with Live CD, but in the extreme case you can try to try again. And the utility from the manufacturer HDD search.

Igor (August 30, 2009, 15:49)

3. And it looks like a poltergeist. :)
In short, the memory is, the Gudramovskaya operative. Probably some kind of incompatibility. Now on his native Hyundai Electronics, a real branded Korean, with a civilian stamp, everything works without failures since in the morning. Even from the night - as I installed. And another system started without problems - Perfect world ran. True damage remaining will have to eliminate. For the first time, my memory returned to a much more killed system therefore there was no result apparently.
Tested the system - without failures. The log of events remained damaged
Dinen. Comodo Firewall is also fine and in his magazine. Daw
tanovil compute some updates and then appeared
Dragoncy. Msfeedssync.exe break into the network. Firefox IE IE.
Not launched at all. What a fig it climbs news feeds to check
Or what's there. Well, about HDD, I have 88% health, but it worked fine in my opinion before the crisis. Maybe it struck badly
When did the new memory fit? In general, I will restore how
OS, update the rest of the stuffing and disk image in acronis. Then there can be more Introt the targets, if I do not pass back. And you need to think what memory to seek or rather find at least something working under my car. At that point, only such available on laptops. And Cureit know and use, since literally half a month ago, I picked up "something" (Neshta), waved to treat on two computers. Now I checked the Cureit-Ohm - everything is clean.
True, he always swears on Giljabi.exe from my LG_SWUpdate directory. But I think everything is fine here. :)

Shl interesting in mind can not be a virus already put up to me? (type from the manufacturer) :))

Igor (September 1, 2009, 19:30)

Heh, in the turmoil was not seen such item as a memory
In one slot. Now I put 1GB Kingston and so far everything is ok. And thinking
What will happen next. Now it has become M1 and M2 and not as on "PC Wizard 2008 physical memory_2gb" screenshot. With another "M1" yes
And I remember that I will support 2GB, 1GBX2. Those. In two slots.
It remains if you put another one in the "bottom" and voila - two-channel
naya Well, who saved here on a sabzh will now know what horrors
They may follow the resulting routine operation.

Sergey (November 18, 2009, 20:50)

Hello, Vladimir! I will be glad to hear your advice.
There is a DDR1 3200 memory plan, 512 MB. What is better to install another bar with the same characteristics (DDR1 3200, 512 MB) or 1 GB bar (to obtain 1.5 GB)? By the way motherboard (FoxConn P4M800P7MA-RS2) has 2 slots for DDR1 and two slots for DDR2. Does it make sense to install DDR2?

(November 18, 2009, 20:57)

Sergey, it is better to install another 1GB and get in the end 1.5GB.
You will most likely not noticize the difference between DDR1 and DDR2, and simultaneously install both types of memory in most cases it is impossible.

Sergey (November 19, 2009, 21:14)

Thank you. And what is the likelihood that the new plank 1GB will work with the old 512MB? I heard that it is better to work with each other identical according to the planks parameters, plus to the same double channel.

Igor (November 24, 2009, 16:58)

They absolutely do not prevent them from worrying if the mother supports such a number and in such slots. Memory must be increased under running applications. There will be no significant difference between 1.5 and 2 GB if the operation of the tank itself is consumed for example 1GB. The difference will be if it costs 1GB and with a working program, 1.5 GB is taken, i.e. "Happing" from the swap and accordingly slows down due to access to HDD. Watch: Task Manager-\u003e Performance-\u003e Peak. How much do you have at your working beloved hard, it is how many RAM and it is necessary. \u003d) Two-channel gives an increase of less than 10% if not confused, which is not the essence as important with the above described. Well, this as they say my IMHO, although it rolls on the noubolages of users. \u003d)

Sergey (February 25, 2010, 00:57)

Artyom (September 15, 2010, 12:51)

mat. My fee is just from that series that is mentioned in this article ASUS SOKET 775 P5LD2 SE. Thank you, Vladimir) I will try.

Anton (January 31, 2013, 14:05)

Hello, the question of the following nature:
Maternity Asus P5LD2 In its description, it is written that you can install the memory operational with a frequency of 667 MHz as possible, but I bought 2 planks on 2GB and the frequency of 800 MHz, I installed the work of the computer very much. Previously stood 1GB OP.
But after that it began to disappear on the hard disk, namely on the "C" disk (there is Windows XP on it)
Can this be due to the restriction of the motherboard?
Or, I caught some kind of virus? Because on the this moment Kaspersky without a license Well, tobish not paid \u003d not working.

(January 31, 2013, 14:09)

Anton, a lot of space disappeared?
Windows has a paging file, it can sometimes depend on the size of RAM.
There is a sleep mode when all the contents of the RAM is saved to the hard disk - and the system reserves the volume equal to the amount of memory always. You can disable it and the place will return.

And maybe just some coincidence.

Vas! (May 19, 2013, 19:34)

Good! Will you tell me: Matpal Asus supports memory up to 800 MHz, now costs 2 to 512 at 533 speeds (PC-4300). Is it possible to extend delivering 1 or 2 GB but 800y memory because ZS-4300 Buy nowhere. Does such a combination of 2x512Mb on 533 and 1 or 2 GB be 800 ??? Thank you.

OPANA. (October 23, 2015, 15:43)

Hello, I have a slots for DDR3 and DDR4 on my mom, can I fix it to 8GB * 2 [Email Protected] Another 8GB * 2 [Email Protected]

Tony (March 27, 2017, 16:29)

I have a question, whether it will work in a Toshiba Satelit A 215 laptop? There is exactly the frequency of 667 hertz in the 800 hertz plank, and is there a risk that will not start at all? And in general, you can shove more than 4 gigs of RAM? Or there 4, - Maximum?

the guest (July 2, 2018, 10:22)

Ha, P5RD2-VM does not start with the 800th memory (officially just 667 ceiling). But she has found a crutch - if you stick together one 667, and another 800, then everything works.

Vadim. (October 10, 2018, 12:08)

aSRock 945GCM-S does not support 800 MHz memory

Description

In addition to the separation of PO bandwidth and containers, modules are divided by:

the presence of an additional memory chip for error correction code. Denote by ECC characters, for example, as follows: PC2-6400 ECC;
the presence of a specialized addressing microcircuit is REGISTER.
"Normal" modules are indicated as "non-registered" or "unbuffered". Register in buffered - "registered" - modules improves the quality of the command-address lines signal (at the price of an additional tact of delay when contacting), which allows you to raise frequencies and use up to 36 memory chips to the module, creating an increased tank modules that are usually used in servers and workers Stations. Almost all Modules that have been released now are also equipped with ECC.
aMB microcircuit (Advanced Memory Buffer). Such modules are called completely buffered (Fully buffered) are denoted by letters F or FB and have another key location on the module. This further development of the idea of \u200b\u200bregistered modules - Advanced Memory Buffer performs buffering not only the signals of the address, but also data, and uses serial tire To the memory controller instead of parallel. These modules cannot be installed in motherboards developed for other types of memory, and the key position is hampered.

As a rule, even if the motherboard supports REGISTERED and UNBUFFERED (normal memory) modules, modules different types (REGISTERED and UNBUFFERED) can not work in conjunction on one channel. Despite the mechanical compatibility of the connector, the registered memory will simply not start in the motherboard designed to apply conventional (non-buffered) memory and vice versa. The presence / absence of ECC in no way affects the situation. All this concerns both the usual DDR and DDR-II.

It is categorically impossible to use registered memory instead of ordinary memory and vice versa. No exceptions. The only exception is currently two-processor LGA1366 boards that work both with normal and registered DDR-III, but it is impossible to mix two types of memory in one system.

Advantages Compared to DDR

Higher bandwidth
As a rule, less power consumption
Improved construction constructing

Disadvantages compared to DDR

Usually higher CAS-latency (from 3 to 6)
The final delays in the same (or even higher) frequencies turn out to be higher

DDR2 gradually displaces DDR3.

Literature

V. Solomenchuk, P. Solomenchuk Iron PC. - 2008. - ISBN 978-5-94157-711-8

Notes

Links

Types of dynamic memory with arbitrary access (DRAM)
Asynchronous	FPM RAM. · EDO RAM.
Synchronous	SDRAM · DDR SDRAM · Mobile DDR (LPDDR) · DDR2 SDRAM · DDR3 SDRAM · DDR4 SDRAM
Graphic	Vram. · Wram. · Mdram. · SGRAM · Gddr. · GDDR2. · GDDR3 · GDDR4 · GDDR5
Rambus.	Rdram. · XDR Dram. · XDR2 Dram.

Wikimedia Foundation. 2010.

The appearance of new platforms on the mass market is becoming increasingly popular with the DDR2 memory, which gradually begins to displace the DDR memory. Initially, there was only the DDR2-400 memory, the DDR2-533 memory was fairly shifted. And now you can already meet the memory DDR2-667, DDR2-675, DDR2-750, DDR2-800, DDR2-900, DDR2-1000 and even DDR2-1066. At the same time, we note that the standardized memory is currently DDR2-533 and DDR2-667. In the near future, the DDR2-800 memory will also be standardized, and therefore many motherboards already support this type of memory. The remaining types of memory are not standardized, and it is not a fact that the motherboard is capable of supporting this memory on the stated clock frequency. The question arises: why do memory manufacturers, competing with each other, are trying to release more and more speeds? The answer is pretty simple - this is a marketing stroke. After all, according to the ordinary buyer, the higher the clock frequency, the better. But is it really possible whether the performance of memory is really completely determined by its clock frequency? Is the high-speed memory type DDR2-1000 in demand today or is it nothing more than competition between memory manufacturers?

It turns out that the clock frequency is far from the only and not even the most important characteristic of the memory that determines its performance. A much more important characteristic is the latency of memory (memory timings), and in this sense, the memory DDR2-800 with large latency will be less productive than the memory DDR2-667 with low latency.

However, to figure out all these nuances and find out what latency is and why this characteristic is more important than the clock frequency, we should first understand how RAM works.

What is the RAM

perative memory (or RAM memory -Random Access Memory) is a memory with arbitrary access.

Since the elementary unit of information is the BIT, the RAM can be viewed as a set of elementary cells, each of which is capable of storing one information batch.

The elementary cell of the RAM is a condenser capable of maintaining an electrical charge for a short period of time, the presence of which can be associated with an information bit. Simply put, when recording a logical unit in a memory cell, the capacitor is charged, when recording zero - discharged. When reading the data, the capacitor is discharged through the reading scheme, and if the capacitor charge was non-zero, then a single value is set to the readout circuit output.

Since the elementary unit of information for modern computers is byte (eight bits), it can be assumed that the elementary memory cell, which can be addressed, does not store, but byte information. Thus, access to memory is not bothering, but toilely.

Memory chips are organized as a matrix, resembling a sheet of paper into a cell, and the intersection of the column and the string of the matrix sets one of the elementary cells. In addition, modern memory chips have several banks, each of which can be considered as a separate matrix with its columns and rows.

In fig. 1 shows a simplified scheme of a memory chip in which there are four banks, each of which contains 8192 lines and 1024 columns. Thus, the capacity of each bank is 8192x1024 \u003d 8192 KB \u003d 8 MB. Given that there are four banks in the chip, it turns out that the total capacity of the chip is 32 MB.

When accessing a particular memory cell, you must specify the address of the desired line and column.

In order to access the memory cell for recording or reading information, you must specify the address of this cell. Taking into account the fact that several memory chips are used in the memory module, and in each chip - several memory banks, first of all, you must specify, in which chip and the can be the cell. For this use special CS, BA0 and BA1 signals.

The CS signal allows you to select the desired memory chip. When the signal is active, access to the memory chip is possible, that is, the chip is activated. Otherwise, the memory chip is unavailable.

BA0 and BA1 signals allow you to address one of four memory banks. Considering that each signal can take one of two values: 0 or 1, combinations 00, 01, 10 and 11 allow you to set the address of four memory banks.

When chip and memory bank are selected, you can access the required memory cell by setting the column address and string. The address of the string and column is transmitted by a special multiplexed MA address bus (Multiplexed Address).

To read the address of the string to the inputs of the memory matrix, a special gating pulse Ras is served (Row Address Strobe). More precisely, this pulse is a change in the signal level from high to low, that is, when switching the RAS signal with high level It is possible to read the address of the string.

At the same time, we note that the reading address itself does not occur at the time of changing the RAS signal, but synchronized with the positive edge of the tacting pulse.

Similarly, the counting of the address of the column occurs when the signal level changes (strobe pulse) CAS # (Column Address Strobe) from a high value to low and synchronized with a positive edge of a tacting pulse.

By the way, we note that, since all the memory events (reading the address of the string and column, the issuance, or data record) are synchronized with the fronts of the tacting pulse, the memory is called synchronous.

RAS # and CAS # pulses are served successively with each other, and the CAS pulse always follows the RAS # pulse, that is, first the selection of the string, and then - the choice of column.

After reading the address of the string and the memory cell column to it, access is available to read or write information. These operations are similar to each other, but a special allowing signal (gating pulse) WE # (Write Enable) is used for recording. If the voltage signal changes from a high level to low, then information is recorded in the selected cell. If the WE # signal remains high, then the information is read from the selected cell.

After all the data is recorded or read from the cells of active dates, you must execute the precharge command that closes the active string and allows you to activate the following line. The commands used to record or read, and the corresponding state of the gating pulses are presented in Table. 1 and in fig. 2.

Table 1. Commands used to record or read memory cells

Memory characteristics

ak is known, its main memory characteristic is its throughput, that is, maximum amount Data that can be considered from memory or write to memory per unit time. It is this feature directly or indirectly reflected in the name of the type of memory.

In order to determine the bandwidth of memory, you need to multiply the system tire frequency to the number of bytes transmitted in one clock. The SDRAM memory has a 64-bit (8-byte) data bus.

For example, the DDR400 memory has a bandwidth of 400 MHz x 8 bytes \u003d 3.2 GB / s. If the memory works in two-channel mode, then the theoretical memory bandwidth is doubled, that is, for the DDR400 memory in two-channel mode, it is 6.4 GB / s. Theoretical bandwidth for various types of memory is displayed in Table. 2.

Table 2. Compliance with the type of memory and theoretical bandwidth

It would seem that the greater the bandwidth of memory, the better. Partly this is true, but only partly. The fact is that the memory bandwidth must be balanced with the throughput of the processor tire. And if the memory bandwidth exceeds the throughput capacity of the processor bus, it is the processor tire that becomes a bottleneck in the system, limiting memory capabilities. If you consider the Intel Pentium 4 processor or new Intel Pentium D dual-core processors, then the clock frequency of the processor tire is 800 or 1066 MHz. Considering that the tire width is 64 bits (or 8 bytes), we obtain that the throughput of the processor tire is 6.4 or 8.5 GB / s. It follows from this that if the system uses a processor with a frequency of FSB 800 MHz, then in one-channel mode for a balanced solution, it is sufficient to use the memory DDR2-800, and in a two-channel - DDR2-400.

Similarly, if a processor is used in the system with a frequency of FSB 1066 MHz, then in one-channel mode for a balanced solution, you will need to use the memory DDR2-1066, and in dual-channel - enough DDR2-533 memory.

Taking into account the fact that the typical situation is to use the memory in two-channel mode, the DDR2-533 memory fully provides a balanced solution.

The question arises: if the memory DDR2-533 provides bandwidth, consistent with the throughput capacity of the processor tire, why then need a faster memory? The fact is that so far we talked only about theoretical, that is, the maximum possible bandwidth, which is implemented only in the case of consistent data transfer - when the data is transmitted to each tact. In a real situation, the theoretical limit is unattainable, since, in addition, it is necessary to take into account the clocks that are necessary to access the memory cell itself, as well as for the memory module settings. In connection with these others important characteristics Memory are memory timings or her latency.

Under latency, it is customary to understand the delay between the commission's arrival and its implementation. In this sense, latency can be compared with the phone call. The time that passes from the dialing of the number (call of the subscriber) and to an answer in the tube, is the latency of the telephone call.

The latency of the memory, which is determined by its timings, is the delays measured in the amounts of clocks between individual teams. Consider the memory timings in more detail. In fig. 3 shows the sequence of commands when reading or writing data into memory. Initially, activation of the desired memory string (Active command) is activated, for which the RAS signal is translated to a low level and the address of the string is read. Next, the recording command (WRITE) or reading (READ) of the data is followed, for which the CAS signal is translated into a low level and the WE signal is set to the proper level. When installing CAS to a low level after coming the positive front of the tacting pulse, the address of the column address is currently at the moment on the address bus, and access to the desired column of the memory matrix is \u200b\u200bavailable. However, the reader or record command cannot follow directly behind the activation command - it is required that between these commands, that is, between the RAS and CAS pulses, there was a certain period of time Ras to Cas Delay (CAS signal delay relative to the RAS signal). This delay measured in the system bus tacks is made to denote TRCD.

After the reading command (records) of data and before issuing the first data element on the bus (data record in the memory cell) passes the period of time called CAS Latency. This delay is measured in the system bus tacks and denotes TCL. Each subsequent data element appears on the data bus in the next tact.

The completion of the change cycle to the memory bank is carried out by feeding the precharge command, leading to the closure of the memory string. After the precharge command and before the new activation team arrives, the time lapse (TRP), called Row Precharge, must pass.

Another type of delay called Active to Precharge Delay is a time interval between the activation command of the memory string and the Precharge command. This delay is indicated by TRAS and is measured in the system bus tacks.

Well, the last type of delay that needs to be mentioned is the speed of commands (Command Rate). Command Rate is a delay in the system bus tacks between the CS # command selection and the activation command of the string. As a rule, the COMMAND RATE delay is one or two clocks (1T or 2T).

Described delays - Ras to Cas Delay (TRCD), CAS Latency (TCL) and ROW PRECHARGE (TRP) - define memory timings recorded as a TCL-TRCD-TRP-TRAS-Command Rate sequence. For example, for the DDR400 module (PC3200), timings may be as follows: 2-3-4-5- (1T). This means that for this module CAS Latency (TCL) is 2 clock, Ras to Cas Delay (TRCD) - 3 Takt, Row Precharge (TRP) - 4 Takta, Active to Precharge Delay (TRAS) - 5 clocks and Command Rate - 1 tact.

It is clear that the smaller the timings, the more high-speed memory. Therefore, if you compare the memory with timing 3-3-3-5- (1t) and the memory with timing 3-2-2-5- (1t), then the latter turns out to be more quickly.

SDR memory

having absorbed with such important memory characteristics as its timings, you can go directly to the principles of memory. Despite the fact that this article is devoted modern memory DDR2, consideration of the principles of memory work We will start with SDR synchronous SDRM (SINGLE DATA RATE).

SDR SDRAM memory provides synchronization of all input and output signals with positive pulse fronts of the clock generator. The entire array of the SDRAM module memory is divided into two independent banks. Such a solution allows you to combine data sample from one bank with an address setting in another bank, that is, at the same time have two open pages. Access to these pages alternates (Bank Interleaving), and respectively delays are eliminated, which ensures the creation of a continuous data stream.

The most common types of SDRAM memory until recently were PC100 and PC133. The figures 100 and 133 determine the frequency of the system tire in megahertz (MHz) that this memory supports. By internal architecture, methods of control and external design, the PC100 and PC133 memory modules are completely identical.

A packet data processing is organized in SDRAM memory, which allows you to refer to a new address of the memory cell column on each clock cycle. In the SDRAM chip there is a meter to build up the address of the memory cell columns to provide fast access to them.

In the SDRAM memory, the kernels and the exchange buffers operate in synchronous mode at the same frequency (100 or 133 MHz). The transfer of each bit from the buffer occurs with each clock of the memory core operation.

The SDR SDRAM memory chart of the SDR memory diagram is shown in Fig. four.

DDR memory

assue DDR SDRAM, which came to replace the SDR memory, provides twice-large bandwidth. DDR abbreviation (DOUBLE DATA RATE) in the name of the memory means a double data transfer rate. In DDR memory, each I / O buffer transmits two bits for one beat, that is, actually operates on a double clock frequency, while remaining completely synchronized with the core of memory. This mode of operation is possible if these two bits are available for an I / O buffer on each memory job. This requires that each read command led to the transmission from the memory kernel to the buffer at once two bits. To this end, two independent transmission lines from the memory core are used to the I / O buffers, from where the bits come to the data bus in the desired order.

Since with this method of organizing the memory of the memory, there is a pre-discontinuity of two bits before passing them to the data bus, it is also called Pre-Fetch 2 (pre-election 2).

In order to synchronize the operation of the memory core and I / O buffers, the same clock frequency is used (the same tacty pulses). Only if in the kernel of the memory itself, the synchronization is carried out on the positive front of the tacting pulse, then in the I / O buffer for synchronization, both positive and negative front of the tacting pulse (Fig. 5) are used. Thus, the transfer of two bits to the input-output buffer in two separate lines is carried out according to the positive front of the tacting pulse, and their issuance to the data bus occurs both by positive and on the negative front of the tacting pulse. This provides two times higher buffer operation and, accordingly, twice the greater memory bandwidth (see Fig. 5).

All other principal characteristics of DDR memory have not changed: the structure of several independent banks allows you to combine data sample from one bank with an address setting in another bank, that is, you can simultaneously have two open pages. Access to these pages alternates (Bank Interleaving), which leads to the elimination of delays and provides the creation of a continuous data stream.

DDR2 memory

if you follow SDR (Single Data Rate) terminology, DDR (Double Data Rate), then the DDR2 memory would be logical to name QDR (Quadra Data Rate), since this standard implies four times a large transmission speed, that is, in the DDR2 standard for batch mode Access data is transmitted four times in one tact. To organize this memory mode, it is necessary that the I / O buffer operates at a quark frequency compared to the memory core frequency. This is achieved as follows: the kernel of memory, as before, is synchronized by the positive front of the tacting pulses, and with the arrival of each positive front for four independent lines, four bits of the information are transmitted to the I / O buffer (sample of four bits per tact). The I / O buffer itself is clocked on the double rate of the memory core and synchronized both by positive and on the negative front of this frequency. In other words, with the arrival of positive and negative fronts, bits are transmitted in multiplex mode to the data bus (Fig. 6). This allows each tact of a memory core operation to transmit four bits to the data bus, that is, in four way to increase the bandwidth of memory.

Compared to the DDR memory, the DDR2 memory allows you to provide the same bandwidth, but with a smaller core frequency. For example, in the DDR400 memory, the kernel functions at a frequency of 200 MHz, and in the DDR2-400 memory at a frequency of 100 MHz. In this sense, the DDR2 memory has significantly large potential opportunities for increasing bandwidth compared with DDR memory.

From theory to practice: DDR2-667 KingMax KLCD48F-A8EB5-ECAS memory

hug the theoretical aspects of the functioning of modern DDR2 memory, we turn from theory to practice. As an example, we will consider the new SDRAM DDR2-667 memory of Kingmax. Stand for testing had the following configuration:

processor: Intel Pentium 4 570 (clock frequency 3.8 GHz, L2 cache 1 MB);
frequency FSB.: 800 MHz;
motherboard: MSI P4N Diamond;
chipset: NVIDIA NFORCE4 SLI Intel Edition;
memory: Two DDR2-667 KingMax KLCD48F-A8EB5-ECAS modules 1 GB each (two-channel mode of operation);
video card: MSI NX6800 ULTRA-T2D512E.

Unfortunately, technical information about KingMax KLCD48F-A8EB5-ECAS modules on the manufacturer's website is not enough. The only thing that managed to find out is about the organization of the module (8-128 MB) and the value of the CAS Latency parameter, which is 5 clocks.

To test the memory, we used the Rightmark Memory Analyzer V 3.55 test package and a set of game benchmarks: Half-Life 2, Doom 3, Farcry 1.3, Unreal Tournament 2004 and 3DMark 2003. In order to increase the load on the processor and the memory when testing has been used by the resolution of 640-480 points. And the video card driver was adjusted for maximum performance.

As it turned out in the testing process, the KLCD48F-A8EB5-ECAS memory modules have default timings (by SPD) and make up a sequence 5-5-5-13- (2t). In this way:

CAS LATENCY (TCL) - 5T;

Ras to Cas Delay (TRCD) - 5T;

ROW PRECHARGE (TRP) - 5T;

Active to Precharge (TRAS) - 13T;

COMMAND RATE - 2T.

In order to estimate the potential ability to accelerate the memory modules (but without compromising stability), we also conducted testing in the low timing mode, which were defined by the method of trial and errors. As it turned out, minimal timings that support these memory modules on the clock frequency of 667 MHz are sequence 4-3-3-5- (2t). In addition, we conducted an overclocking of memory on the clock frequency to estimate the maximum possible clock frequency supported by these modules when working in two-channel mode.

For testing using the RightMark Memory Analyzer V 3.55 test package, the presets are built in Benchmark:

RAM PERFORMANCE STREAM;

Average Memory Bandwidth, SSE2;

Maximal Ram Bandwidth, Software Prefetch, SSE2;

Average Ram Latency;

Minimal Ram Latency, 16 MBYTE BLOCK, L1 Cache Line.

FROM detailed description Every preset can be found on www.rightmark.org or www.ixbt.com.

Test results using the RightMark Memory Analyzer V 3.55 test package are presented in Table. 3.

Using the Test Package Rightmark Memory Analyzer V 3.55

As follows from test results, default timings (by SPD) are highly overestimated. Reducing timings does not affect the stability of the memory modules, but leads to a significant increase in memory bandwidth and to reduce latency. Thus, the maximum memory bandwidth during timings 5-5-5-13- (2T) is 5967.3 MB / s (reading operation, preset Maximal Ram Bandwidth, Software Prefetch, SSE2). At the same time, with a decrease in timings to 4-3-3-5- (2t), the bandwidth increases to 6294.9 MB / s, that is, 5.5%. Note that the value is 6294.9 MB / s close to the theoretical limit of the throughput of the processor tire, which in this case is 6.4 GB / s.

Increasing the clock frequency up to 710 MHz does not affect the stability in memory, however, it is not possible to achieve a significant increase in memory performance in this case, which once again confirms the fact that the change in memory timings has a significantly greater impact on memory capacity, rather than an increase in the clock frequency. .

Now let's turn to the results of the game tests (Table 4). As you can see, a decrease in memory timings allows (albeit slightly) to increase the results in all game tests. At the same time, an increase in the clock memory frequency is not reflected on the test results.

***

So, if we talk about the considered KingMax KLCD48F-A8EB5-ECAS memory modules, you can state that in combination with MSI P4N Diamond motherboard, and therefore, with the NVIDIA NForce4 SLI Intel Edition chipset, these modules are guaranteed stable work And perfectly accelerate by reducing timings. That is why we decided to assign KingMax KLCD48F-A8EB5-ECAS modules "Editorial recommends".

The editors are appreciated by Kingmax(www.kingmax.com. ) For providing KingMax KLCD48F-A8EB5-ECAS memory modules.

RAM is used to temporarily storing the data required for the operating system and all programs. Runifying memory should be enough if it is not enough, the computer begins to slow down.

The board with memory chips is called the memory module (or bar). The memory for a laptop, in addition to the size of the planks, nothing is different from memory for the computer, so when you select, follow the same recommendations.

For office Computer One DDR4 strip is enough for 4 GB with a frequency of 2400 or 2666 MHz (it is almost the same).
RAM MEMORY CRUCIAL CT4G4DFS824A

For a multimedia computer (movies, simple games), it is better to take two DDR4 strips with a frequency of 2666 MHz to 4 GB, then the memory will work in a faster two-channel mode.
RAM BALLISTIX BLS2C4G4D240FSB

For gaming computer The middle class can be taken one DDR4 bar4 to 8 GB with a frequency of 2666 MHz so that in the future you can add another and better if it is the running model simply.
RAM CRUCIAL CT8G4DFS824A

And for a powerful gaming or professional PC, you need to immediately take a set of 2 DDR4 operators of 8 GB, while the frequency of 2666 MHz will be quite enough.

2. How much memory you need

For an office computer designed to work with documents and accessing the Internet, with the head of a single memory strip on 4 GB.

For a multimedia computer that can be used to view video in high quality and undemanding games, there are enough 8 GB of memory.

For a mid-class gaming computer, a minimum option is 8 GB of RAM.

For a powerful gaming or professional computer, 16 GB of memory is necessary.

A larger amount of memory may only be needed for very demanding professional programs and no usual users needed.

Memory capacity for old PC

If you decide to increase the amount of memory on the old computer, then you will note that 32-bit versions of Windows do not support more than 3 GB of RAM. That is, if you set 4 GB of RAM, the operating system will see and use only 3 GB.

As for the 64-bit versions of Windows, they will be able to use all installed memorybut if you have an old computer or there is an old printer, then they may not be drivers for these oS. In this case, before purchasing memory, set the 64-bit bit windows version And check if you work. I also recommend to look at the manufacturer's website of the motherboard and see what volume of modules and the total amount of memory it supports.

Note that the 64-bit operating systems spend 2 times more memory, for example, Windows 7 x64 takes about 800 MB under its needs. Therefore, 2 GB of memory for such a system will be little, preferably at least 4 GB.

Practice shows that modern Windows 7.8.10 operating systems are completely disclosed at a memory of 8 GB. The system becomes more responsive, the program opens faster, and jerks (friezes) disappear in games.

3. Memory types

Modern memory has a DDR SDRAM type and is constantly improving. So the DDR and DDR2 memory is already obsolete and can only be used on old computers. DDR3 memory is no longer expedient to use on new PCs, it came to replace the faster and promising DDR4.

Note that the selected memory type should support the processor and motherboard.

Also new processors, for compatibility considerations, can support DDR3L memory, which differs from the usual DDR3 reduced voltage from 1.5 to 1.35 V. Such processors will be able to work with normal DDR3 memory, if you already have it, but processor manufacturers do not recommend this - the excessive degradation of memory controllers designed for DDR4 with even more low voltage 1.2 V.

Memory type for old PC

Outdated DDR2 memory costs several times more modern memory. Planck DDR2 on 2 GB stands 2 times more expensive, and a DDR2 plan2 on 4 GB is 4 times more expensive than a DDR3 or DDR4 strip.

Therefore, if you want to significantly increase memory on the old computer, then a more optimal option will be the transition to a more advanced platform with the motherboard and if the processor is needed to support DDR4 memory.

Calculate how much it will cost you, it is possible to sell an old motherboard with an old motherboard and acquire new, let not the most expensive, but more modern components.

Motherboard connectors for memory installation are called slots.

Each type of memory (DDR, DDR2, DDR3, DDR4) corresponds to its slot. DDR3 memory can only be installed in the motherboard with DDR3, DDR4 slots - with DDR4 slots. Motherboards supporting the old DDR2 memory no longer produce.

5. Memory characteristics

The main characteristics of the memory on which its speed depends is the frequency and timings. The speed of memory does not have such a strong influence on the overall performance of the computer as a processor. However, it is often possible to purchase a faster memory not much more expensive. Fast memory We need primarily for powerful professional computers.

5.1. Memory frequency

The frequency has the greatest value to the speed of memory. But before purchasing it, you must make sure that the processor and motherboard also support the necessary frequency. Otherwise, the actual frequency of memory will be lower and you will simply overpay for not being used.

Cheap motherboards support a lower maximum memory frequency, for example, for DDR4 is 2400 MHz. Maternally and high-class motherboards can support higher frequency memory (3400-3600 MHz).

But with the processors the case is different. Old processors with DDR3 memory support can support memory with a maximum frequency of 1333, 1600 or 1866 MHz (depending on the model). For modern processors with DDR4 memory support, the maximum supported memory frequency can be 2400 MHz or higher.

The 8th generation Intel processors and above, as well as AMD Ryzen processors support DDR4 memory with a frequency of 2400 MHz or higher. At the same time in their model row There are not only powerful expensive processors, but also the processors of average and budget class. Thus, you can assemble a computer on the most modern platform with an inexpensive processor and DDR4 memory, and in the future, change the processor and get the highest performance.

The main one is the memory of DDR4 2400 MHz, which is supported by the most modern processors, motherboards and costs as much as DDR4 2133 MHz. Therefore, to acquire DDR4 memory with a frequency of 2133 MHz today does not make sense.

What frequency of memory is supported by one or another processor can be found on the sites of manufacturers:

By model number or serial number It is very easy to find all the characteristics of any processor on the site:

Or simply enter the model number in the Google search system or Yandex (for example, Ryzen 7 1800x).

5.2. High frequency memory

Now I want to touch on another interesting point. On sale you can meet the RAM of much higher frequency, which supports any modern processor (3000-3600 MHz and above). Accordingly, many users are wondering how can it be?

It's all about the technology developed by Intel, Extreme Memory Profile (XMP). XMP allows memory to work at a higher frequency than officially supports the processor. XMP must support both memory itself and the motherboard. High frequency memory simply cannot exist without supporting this technology, but not all motherboards can boast its support. Basically, it is more expensive models above the middle class.

The essence of XMP technology is that the motherboard automatically increases the frequency of the memory bus, thanks to which the memory begins to work at its higher frequency.

AMD has a similar technology called AMD Memory Profile (AMP), which was supported by old motherboards for AMD processors. These motherboards usually supported XMP modules.

Purchase more expensive memory with a very high frequency and motherboard with XMP support It makes sense for very powerful professional computers equipped with a top processor. In the middle-class computer, this will be thrown on the wind money, since everything will be paid to the performance of other components.

In games, the frequency of memory has a slight effect and there is no particular sense, it will be enough to take on a 2400 MHz, or for 2666 MHz if the price difference is small.

For professional applications, you can take memory with the frequency higher - 2666 MHz or if you want and allow funds for 3000 MHz. The difference in performance here is more than in games, but not cardinal, so there is no sense to drive with the frequency of memory.

Once again I remind you that your motherboard must support the memory of the required frequency. In addition, sometimes Intel processors begin to work unstable at a memory frequency above 3000 MHz, and Ryzen this limit is about 2900 MHz.

Timins are called delays between read / write / copy data in RAM. Accordingly, than these delays less, the better. But the timings have a much smaller impact on the speed of memory, than its frequency.

The main timings, which are indicated in the characteristics of the memory modules of only 4.

Of these, the most important is the first digit, which is called latency (CL).

Typical latency for DDR3 memory 1333 MHz - Cl 9, for DDR3 memory with higher frequency - Cl 11.

Typical latency for DDR4 2133 MHz - Cl 15, for DDR4 memory with higher frequency - CL 16.

It is not necessary to purchase memory with latency higher than specified, as it speaks about the total low level of its technical characteristics.

Usually, memory with lower timings is more expensive, but if the difference in price is not significant, then the preference is followed to give memory with lower latency.

5.4. Supply voltage

Memory may have different supply voltage. It can be both standard (generally accepted for a specific type of memory) and elevated (for enthusiasts) or vice versa reduced.

This is especially important if you want to add memory to a computer or laptop. In this case, the voltage of new slats should be the same as the available. Otherwise, problems are possible, since most motherboards cannot set different voltages for different modules.

If the voltage is displayed on a strip with a lower voltage, then the other may not be enough power and the system will not work stably. If the voltage is displayed on a strip with a higher voltage, then the memory calculated for fewer voltage can fail.

If you collect a new computer, then this is not so important, but to avoid possible compatibility issues with the motherboard and replacing or expansion of memory in the future, it is better to choose a standards with standard supply voltage.

Memory, depending on type, has the following standard supply voltages:

DDR - 2.5 in
DDR2 - 1.8 V
DDR3 - 1.5 in
DDR3L - 1.35 V
DDR4 - 1.2 in

I think you drew attention to the fact that the list is DDR3L memory. This is not a new type of memory, but the usual DDR3, but with reduced power voltage (LOW). It is this memory that is needed for the Intel processors of the 6th generation and higher, which support both the DDR4 memory and DDR3. But it is better in this case to collect the system on the new DDR4 memory.

6. Marking of memory modules

Memory modules are marked depending on the type of memory and its frequency. The labeling of the DDR memory modules starts with PC, then there is a digit that denotes generation and speed in megabytes per second (MB / s).

In such marking, it is inconvenient to navigate, it is enough to know the type of memory (DDR, DDR2, DDR3, DDR4), its frequency and latency. But sometimes, for example on ad sites, you can see the marking rewritten from the plank. Therefore, so that you can navigate in this case, I will give a classic labeling, with a type of memory, its frequency and typical latency.

DDR - outdated

PC-2100 (DDR 266 MHz) - CL 2.5
PC-2700 (DDR 333 MHz) - CL 2.5
PC-3200 (DDR 400 MHz) - CL 2.5

DDR2 - outdated

PC2-4200 (DDR2 533 MHz) - Cl 5
PC2-5300 (DDR2 667 MHz) - Cl 5
PC2-6400 (DDR2 800 MHz) - Cl 5
PC2-8500 (DDR2 1066 MHz) - Cl 5

DDR3 - Obsolete

PC3-10600 (DDR3 1333 MHz) - Cl 9
PC3-12800 (DDR3 1600 MHz) - Cl 11
PC3-14400 (DDR3 1866 MHz) - Cl 11
PC3-16000 (DDR3 2000 MHz) - Cl 11

PC4-17000 (DDR4 2133 MHz) - Cl 15
PC4-19200 (DDR4 2400 MHz) - Cl 16
PC4-21300 (DDR4 2666 MHz) - CL 16
PC4-24000 (DDR4 3000 MHz) - CL 16
PC4-25600 (DDR4 3200 MHz) - Cl 16

DDR3 and DDR4 memory can have a higher frequency, but only top processors and more expensive motherboards can work with it.

7. Construction of memory modules

Memory bar can be one-sided, double-sided, with radiators or without.

7.1. Placing chipov

Chips on memory modules can be placed on one side of the board (one-sided) and on both sides (double-sided).

It does not matter if you acquire memory for a new computer. If you want to add memory to the old PC, it is desirable that the location of chips on the new bar is the same as on the old one. This will help avoid compatibility issues and increase the probability of memory in two-channel mode, which we will talk about in this article.

Now you can find many memory modules with aluminum radiators of various colors and shapes.

The presence of radiators can be justified at the memory of DDR3 with a high frequency (1866 MHz or more), as it warms it harder. In this case, ventilation should be well organized in the case.

The modern DDR4 operative with a frequency of 2400, 2666 MHz is practically not heated and radiators on it will be purely decorative. They may even interfere, because after a while they score dust, which is difficult to clean out of them. In addition, this memory will be somewhat more expensive. So, if you want, this can be saved, for example, taking excellent CRUCIAL memory for 2400 MHz without radiators.

Memory with a frequency of 3000 MHz has also increased supply voltage, but also heats up not much and in any case there will be radiators.

8. Memory for laptops

The memory for laptops differs from memory for stationary computers only the size of the memory module and marked SO-DIMM DDR. As well as for stationary computers, laptop memory has types DDR, DDR2, DDR3, DDR3L, DDR4.

In frequency, timings and power voltage memory for laptops does not differ from memory for computers. But laptops are equipped with only 1 or 2 memory slots and have more stringent limitations of the maximum volume. Be sure to specify these parameters before selecting the memory for specific model laptop.

9. Memory Modes

Memory can work in single channel (SINGLE CHANNEL), two-channel (Dual Channel), three-channel (Triple Channel) or four-channel mode (Quad Channel).

In one-channel mode, data recording occurs sequentially into each module. In multichannel modes, the data record occurs in parallel to all modules, which leads to a significant increase in the speed of the memory subsystem.

One-channel mode of memory operation is limited only hopelessly outdated motherboards with DDR memory and the first models with DDR2.

All modern motherboards support two-channel memory mode, and three-channel and four-channel mode support only some single models of very expensive motherboards.

The main condition for the operation of the two-channel mode is the presence of 2 or 4 memory schedules. For a three-channel mode, you need 3 or 6 memory schedules, and for four-channel 4 or 8 slats.

It is desirable that all memory modules are the same. Otherwise, the work in two-channel mode is not guaranteed.

If you want to add memory to the old computer and your motherboard supports a two-channel mode, try to choose the most identical to all the parameters of the bar. It is best to sell old and buy 2 new identical planks.

In modern computers, memory controllers were transferred from the motherboard to the processor. Now it is not so important that the memory modules are the same, since the processor in most cases can still activate the two-channel mode. This means that if you want to add memory to a modern computer in the future, it will not necessarily look exactly the same module, it is enough to choose the most similar on the characteristics. But still I recommend that the memory modules were the same. It will give you a guarantee of its fast and stable work.

With the transfer of memory controllers to the processor, 2 more two-channel memory modes - Ganged (paired) and unganged (unpaired) appeared. If the memory modules are the same, the processor can work with them in Ganged mode, as before. If the modules differ in terms of characteristics, then the processor can activate the UnganGed mode to eliminate the disks in memory. In general, the speed of memory in these modes is almost the same and has no difference.

The only disadvantage of the two-channel regime is that several memory modules are more expensive than one of the same volume. But if you are not very constrained in the means, then buy 2 planks, the speed of memory will be significantly higher.

If you need, say 16 GB RAM, but you can not allow it to yourself, you can purchase one bar on 8 GB to add another same in the future. But it is still better to acquire two identical strips at once, since then it may not work out to find the same and you will come across the problem of compatibility.

10. Memory module manufacturers

One of the best price / quality ratios today has the memory of the immaculately proven brand Crucial, which has modules from budget to Gamers (Ballistix).

Along with him, the Corsair brand enjoyed by the well-deserved popularity, whose memory is somewhat more expensive.

As an inexpensive, but high-quality alternative, I especially recommend the Polish GOODRAM brand, which has a low timing planks for a low price (Line Play).

For an inexpensive office computer, it will be enough simple and reliable memory of the production of AMD or Transcend. They have greatly proven themselves and practically no problems with them.

In general, Korean companies Hynix and Samsung are considered leaders in memory production. But now the modules of these brands are massively produced on cheap Chinese factories and there are a lot of fakes among them. Therefore, I do not recommend purchasing the memory of these brands.

The exception can be the memory modules of the Hynix Original and Samsung Original, which are manufactured in Korea. These planks are usually blue, their quality is considered better than in China made in China and the warranty is somewhat higher. But in speed characteristics, they are inferior to memory with lower timings of other high-quality brands.

Well, for enthusiasts and lovers of moding there are affordable overclocker brands GEIL, G.SKILL, TEAM. Their memory is distinguished by low timings, high acceleration potential, unusual appearance and costs a little cheaper Corsair brand.

The sale also has a large range of memory modules from a very popular Kingston manufacturer. The memory sold under the Kingston budget brand has never been different. But they have a top HYPERX series, which is well-deserved, which can be recommended for the acquisition, however, the price for it is often overestimated.

11. Memory packaging

It is better to acquire memory in individual packaging.

Usually she is more high Quality And the probability of damage during transportation is significantly lower than the memory that comes without packaging.

12. Increase memory

If you plan to add memory to an existing computer or laptop, first find out what maximum volume of planks and the total memory supports your motherboard or laptop.

Also specify how many slots for memory on the motherboard or in a laptop, how many of them are occupied and which planks are installed in them. It is better to do it visually. Open the housing, remove the memory bar, consider them and rewrite all the characteristics (or make a photo).

If for some reason you do not want to climb into the case, then you can see the memory parameters in the program on the SPD tab. Thus, you will not recognize a one-sided strap or double-sided, but you can find out the memory characteristics if there are no stickers on the bar.

There is a basic and efficient memory frequency. CPU-Z and many similar things show basic frequency, It must be multiplied by 2.

After you learn to what volume can you increase the memory, how many free slots and what memory you have installed, you can start exploring memory increases.

If all the memory slots are occupied, then the only possibility of increasing memory remains replacing existing planks for new larger volume. And the old planks can be sold on the announcement website or pass on exchange to a computer shop when buying new ones.

If there are free slots, you can add to the already existing memory straps new. It is desirable that new planks are as close as possible according to the characteristics already installed. In this case, you can avoid different problems Compatibility and increase the chances of the fact that the memory will work in two-channel mode. For this, the following conditions must be followed, in importance.

The type of memory must match (DDR, DDR2, DDR3, DDR3L, DDR4).
The supply voltage of all slats should be the same.
All planks must be one-sided or double-sided.
The frequency of all slats should coincide.
All planks must be the same volume (for a two-channel mode).
The number of slats should be even: 2, 4 (for two-channel mode).
It is desirable to coincide latency (CL).
It is desirable that the planks were the same manufacturer.

The easiest way to start a choice from the manufacturer. Choose in the online store directory planks of the same manufacturer, volume and frequency, as you have installed. Make sure that the supply voltage coincides and check the consultant one-sided or double-sided. If there is still a coincidence and latency, it is generally good.

If you failed to find similar by the characteristics of the plank of the same manufacturer, then choose all others from the list of recommended. Then, look for the planks of the desired volume and frequency, check the supply voltage and specify one-sided or double-sided. If you failed to find similar plates, then look in another store, directory or on the list of ads.

Always the best option to sell all the old memory and buy 2 new identical planks. If the motherboard does not support the planks of the desired volume, you may have to buy 4 identical planks.

13. Setting up filters in the online store

Go to the "RAM" section on the seller's website.
Select Recommended Manufacturers.
Select the form factor (DIMM - PC, SO-DIMM - laptop).
Select the type of memory (DDR3, DDR3L, DDR4).
Select the required volume of the slats (2, 4, 8 GB).
Select the frequency supported by the processor (1600, 1866, 2133, 2400 MHz).
If your motherboard supports XMP, add a higher frequency memory to select (2666, 3000 MHz).
Sort sort the price.
Consistently view all positions starting with cheaper.
Select a few schedule suitable frequency.
If the price difference is acceptable for you, take the bar with a greater frequency and less latency (CL).

Thus, you will get an optimal price / quality ratio / speed memory for the minimum possible cost.

14. Links

RAM RAM CORSAIR CMK16GX4M2A2400C16
RAM RAM CORSAIR CMK8GX4M2A2400C16
RAM MEMORY CRUCIAL CT2K4G4DFS824A