Pico ATX The firm has developed this specification. The key distinctions of ATX from AT. Starting power supply

Form factor of computer enclosures and motherboards - one of their significant characteristics. Frequently faced with a misunderstanding of the difference between ATX and MATX or when assembling a new system, or when the old upgrade is upgraded. Most familiar only with these abbreviations, although in the context there are other. Both standards are similar to each other, and to a number of characteristics of a number of components are imposed by identical requirements, so consider ATX and MATX worth it for motherboards - the form factor here will be decisive.

Definition

ATX- Form factor of full-size motherboards for desktop computers, determining dimensions, number of ports and connectors, other characteristics. Also is the form factor of personal desktop computers determining the size of the hull, the location of the attachments, placement, size and electrical accuracy of the power supply.

matx - Form factor of motherboards of reduced dimensions and with a trimmed number of ports and interfaces. Also - form factor of system blocks.

Comparison

The difference between ATX and MATX is primarily in size. Full-size motherboards are installed in Full-Tower and Midi-Tower form factor housing, MATX boards are also in mini-tower. The standard Sizes of ATX boards are 305x244 mm, although it can be slightly smaller widths to 170 mm. The standard sizes of MATX boards (often referred to as Micro-ATX) are 244x244 mm, but can be cut to 170 mm. Very stringent standards are not, and the difference is several mm from a manufacturer - the case is usual and nothing affecting. But the places for fastenings are standardized by the form factor rigidly, and absolutely always coincide with the body holes for installing motherboards. Visually is determined by this: the first from the plug vertical row of holes is universal, the second is designed for MATX, the third is for ATX boards. In small MATX builds, install the ATX fee will not work, on the contrary, in most cases, the installation will not cause difficulties.

Another difference is in the number of ports and interfaces. Standardization This is not subject to and remains at the discretion of the manufacturer, however, mainly on MATX boards, the minimum gentlemansky set: two, and not four, as in ATX, slot for RAM, fewer SATA and USB interfaces, one video output is displayed on the rear panel (if There is), I / O ports, often combined, minimum USB, most often there are no excess of essentially eSATA or HDMI. All motherboards are equipped with an Ethernet port today. The number of PCI connectors on MATX boards is minimal, so that the video card is plus another pair of extension boards - the limit of dreams. Also, due to the reduction of area on small boards, integration is always relevant, plus the number of spaced parts is less.

In practice, the user of the computer differences between the factors of motherboards will not find. Due to the small size of the enclosures and the "cuminess", MATX electronics can warm up, and the installation of new components due to the saved space may be uncomfortable.

Conclusions Site

ATX is larger both as a form factor of motherboards, and as body factor.
mATX has a trimmed functionality due to reducing the number of ports and connectors.
MATX boards can be installed in the ATX housing, and not vice versa.
In some cases, MATX cause inconvenience when installing components.

To date, there are four prevailing sizes of motherboards - AT, ATX, LPX and NLX. In addition, there are reduced AT format options (Baby-AT), ATX (MINI-ATX, MICROATX) and NLX (MicronLX). Moreover, the extension to the Microatx specification is recently released, which adds a new form factor to this list - FlexATX. All these specifications that define the shape and size of motherboards, as well as the location of the components on them and the features of the enclosures, and are described below.

AT.

AT form factor is divided into two, differing in the size of modifications - AT and Baby AT. The size of a full-sized AT board reaches up to 12 "wide, which means that such a fee is unlikely to fit into most of today's enclosures. Installation of such a board will certainly interfere with the discs for drives and hard drives and power supply. In addition, the location of the board components on the large A distance from each other can cause some problems when working on large clock frequencies. Therefore, after motherboards for the processor 386, this size is no longer found.

Thus, the only motherboards performed in the AT form factor are available on a wide sale, these are the boards of the appropriate Baby AT formats. Baby AT 8.5 "width and 13" boards. In principle, some manufacturers can reduce the length of the board to save material or for some other reasons. For fastening the board in the case, three rows of holes are made in the board.

All AT fees have common features. Almost everyone has consecutive and parallel ports that are attached to the motherboard through the connecting plates. They also have one keyboard connector, sold on the card in the rear. The processor socket is installed on the front side of the board. SIMM and DIMM slots are located in various places, although they are almost always located at the top of the motherboard.

Today, this format smoothly goes down from the scene. Part of the firms still produces some of their models in two versions - Baby AT and ATX, but this happens more and less. Moreover, more and more new features provided by operating systems are implemented only on ATX motherboards. Not to mention easily about the convenience of work - so, most often on Baby AT fees, all the connectors are collected in one place, as a result of which cables from communication ports stretch almost through the entire motherboard to the back of the case, or from IDE and FDD ports - to Front. The sockets for memory modules that are almost driven by a power supply. With the limited freedom of action within a very small MINITOWER space, it is, to put it mildly, uncomfortable. In addition, the issue of cooling is unsuccessfully resolved - the air does not receive directly to the most in need of cooling part of the system - processor.

LPX.

Even before the appearance of ATX, the first results of attempts to reduce the cost of PC was the LPX form factor. Designed for use in SLIMLine or Low-Profile enclosures. The task was solved by a rather innovative offer - the introduction of the rack. Instead of inserting the extension cards directly into the motherboard, in this embodiment they will interfere with the vertical rack connected to the board parallel to the motherboard. This made it possible to significantly reduce the height of the case, since it is usually the height of the expansion cards affects this parameter. The maximum number of connected cards has become per compactness - 2-3 pieces. Another innovation that began to be widely applied precisely on LPX boards is an integrated video chip. The size of the housing for LPX leaves 9 x 13 "", for Mini LPX - 8 x 10 ".

After the appearance of NLX, LPX began to be crowned with this form factor.

ATX

It is not surprising that the ATX factor in all its modifications is becoming increasingly popular. In particular, it concerns the boards for processors on the P6 bus. So, for example, the LUCKYSTAR motherboards preparing for this year for these processors 4 will be executed in Mini-ATX, 3 - ATX format, and only one - Baby AT. And if you still consider that motherboards for Socket7 today is much less done, at least because of a much smaller number of new chipsets for this platform, then ATX wins a convincing victory.

And no one can say that she is unreasonable. The ATX specification, proposed by Intel in 1995, is aimed at correcting all the shortcomings, which revealed with time at the AT form factor. And the decision, in fact, was very simple - turn the Baby AT fee for 90 degrees, and make appropriate corrections in the design. By the time Intel had already experienced in this area - LPX Form factor. In ATX, the best sides and Baby AT and LPX were made: Baby AT was taken expansion, and from LPX - high integration of components. That's what happened as a result:

Integrated I / O port connectors. On all modern fees, the I / O port connectors are present on the board, so it is quite natural that the solution looks like on it and their connectors, which leads to a fairly significant decrease in the number of connecting wires inside the case. In addition, at the same time, among the traditional parallel and serial ports, the keyboard connector, there was a place for beginners - PS / 2 and USB ports. In addition, as a result, the value of the motherboard decreased slightly, due to the decrease in cables in the kit.
Significantly increased convenience of access to memory modules. As a result of all changes in the socket for memory modules moved further from the slots for motherboards, from the processor and power supply. As a result, the memory increase has become in any case a minute case, whereas on Baby AT motherboards sometimes have to take a screwdriver.
Reduced distance between the board and discs. The IDE and FDD controller connectors moved almost close to the devices connected to them. This reduces the length of the cables used, thereby increasing the reliability of the system.
Diastrcing processor and slots for extension boards. The processor socket is moved from the front of the card to the back, next to the power supply. This allows you to install full-sized fees in expansion slots - the processor does not interfere. In addition, the problem with cooling was solved - now the air is suused by the power supply, blows the processor directly.
Improved interaction with power supply. Now it uses one 20-pin connector, instead of two, as on AT boards. In addition, the possibility of managing the motherboard is added - switching on at the right time or by the onset of a specific event, the ability to turn on from the keyboard, turn off the operating system, etc.
Voltage 3.3 V. Now the supply voltage is 3.3 V, very widely used by the modern components of the system, (take at least PCI cards!) Comes from the power supply. In AT payments, a stabilizer installed on the motherboard was used to obtain it. In ATX-cards, the need for it disappears.

The specific size of motherboards is described in the specification in many respects on the basis of the convenience of developers - from the standard plate (24 x 18 '') either two ATX cards (12 x 9.6 ''), or four - mini-aTX (11.2 x 8.2 '') . By the way, compatibility with old cases was also taken into account - the maximum ATX width of the board, 12 '', almost identical to AT boards, so that there was an opportunity to use ATX in AT package without much effort. However, today it relates more to the field of pure theory - AT Corps still need to manage to find. Also, as far as possible, the mounting holes in the ATX board fully correspond to AT and Baby AT formats.

microatx

The ATX form factor was designed at the time of the heyday of Socket 7 systems, and today it does not correspond to the time in it today. For example, a typical combination of slots, based on the specification, looked like 3 ISA / 3 PCI / 1 adjacent. Somewhat irrelevant today, isn't it? ISA, no AGP, AMR, etc. Again, in any case, 7 slots are not used in 99 percent cases, especially today, with such chipsets as MVP4, SIS 620, i810, and other preparing for the production of similar products. In general, for cheap PC ATX - empty resource trips. Based on similar considerations in December 1997, the Microatx format specification was presented, the ATX modification of the board, designed for 4 slots for expansion boards.

In fact, changes compared to ATX, turned out to be minimal. Up to 9.6 x 9.6 '' decreased the size of the board, so it has become completely square, the size of the power supply decreased. The input / output connectors block remained unchanged, so Microatx board can be with minimal modifications used in ATX 2.01 housing.

NLX

Over time, the LPX specification, like Baby AT, has ceased to meet the requirements of time. New processors have come out, new technologies appeared. And it was no longer able to provide acceptable spatial and thermal conditions for new low-profile systems. As a result, just as ATX came to replace the Baby AT, as well as in 1997, as the development of the idea of \u200b\u200bLPX, which takes into account the emergence of new technologies, the NLX form factor specification appeared. The format aimed at applying low-profile cases. When it was created, it was taken into account both technical factors (for example, the appearance of AGP and DIMM modules, the integration of audio / video components on the motherboard) and the need to provide greater convenience in service. So, for assembling / disassembling many systems based on this form factor, the screwdriver is not required at all.

As can be seen in the scheme, the main features of the NLX motherboard, this is:

Stand for expansion cards located on the right edge of the board. Moreover, the motherboard is freely disconnected from the rack and extends from the housing, for example, to replace the processor or memory.
The processor located in the left front corner of the board is directly opposite the fan.
In general, the grouping of high components, such as processor and memory, in the left end of the board to allow accommodation at the rack full-size expansion cards.
Finding at the rear end of the board of blocks of I / O connectors is single (in the extension boards) and double height, to accommodate the maximum number of connector.

In general, the rack is a very interesting thing. In fact, this is one motherboard, divided into two parts - a part where the system components are actually located, and connected to it after 340 pin connector at an angle of 90 degrees, which contains all kinds of input / output components - extension cards, port connectors, drives Data where power is connected. Thus, firstly increases the convenience of service - there is no need to access the components unnecessary at the moment. Secondly, the manufacturers as a result have greater flexibility - one model of the main board is made, and the rack under each specific customer, with the integration of the necessary components.

In general, this description does not remind you? The rack, fastening on the motherboard, to which certain input / output components are made, instead of being integrated on the motherboard, and all this serves to simplify the maintenance, give greater flexibility to manufacturers, etc.? That's right, after some time, after the NLX specification output, the AMR specification appeared, which describes the similar ideology for ATX boards.

Unlike rather strict other specifications, NLX provides producers much more freedom in decision making. The size of the NLX motherboard ranges from 8 x 10 '' to 9 x 13.6 ''. NLX Corps must be able to be controlled both with these two formats and with all intermediate. Typically, the boards fit into the minimum dimensions are indicated as mini NLX. It is also worth mentioning not essential detail: NLX USB ports housing are located on the front panel - very convenient for identification solutions of the E.Token type.

It remains only to add that according to the specification, some places on the board are required to remain free, providing opportunities for expanding the functions that will appear in future versions of the specification. For example, to create on-based NLX form factor motherboards for servers and workstations.

WTX.

However, on the other side, powerful workstations and servers of the AT and ATX specification servers are also not quite suitable. There's own problems where the cost is plays not the most important role. The forefront over the provision of normal cooling, the placement of large amounts of memory, convenient support for multiprocessor configurations, the high power of the power supply, the placement of a greater number of port drives of data storage controllers and I / O ports. So in 1998 the WTX specification was born. Oriented to support dual processor motherboards of any configurations, support for today's and tomorrow's video cards and memory.

Particular attention, perhaps, it is worth paying two new components -Board Adapter Plate (BAP) and Flex Slot.

In this specification, the developers tried to move away from the usual model when the motherboard is attached to the housing through the fasteners located in certain places. Here it is attached to the BAP, and the attachment method is left at the conscience of the manufacturer of the board, and the standard BAP is attached to the body.

In addition to the usual things, such as the size of the board (14 x 16.75 "), the characteristics of the power supply (up to 850 W), etc., the WTX specification describes the Flex Slot architecture - in a sense, AMR for workstations. Flex Slot is designed to improve the convenience of servicing, give additional flexibility to developers, reduce the exit of the motherboard to the market. Looks like a Flex slot card something like this:

Any PCI, SCSI or IEEE 1394 controllers, sound, network interface, parallel and serial ports, USB, tools for monitoring the system of the system can be placed on such maps.

Samples of WTX boards should appear in the June area, and serial samples in the third quarter of 1999.

Flexatx

Finally, just as an ATX appeared from ideas in Baby AT and LPX, the development of MicroAtx and NPX specification was the appearance of FlexATX form factor. This is not even a separate specification, but just an addition to the Microatx specification. Looking at the success of the IMAC, in which, in essence, nothing new except for the appearance and was not, the PC manufacturers also decided to go on this path. And the first was the first intel, in February at Intel Developer Forum, who announced the FlexATX - motherboard, on the area of \u200b\u200binterest on 25-30 smaller than MicroATX.

Theoretically, with some modifications, the FlexATX board can be used in the housings corresponding to the ATX 2.03 or MicroATX 1.0 specifications. But for today's corps, there are enough platforms without it, it was a question of fastened plastic structures, where such compactness is needed. There, on IDF, Intel, and demonstrated several possible options for such buildings. The fantasy of designers was raised to the glory - vases, pyramids, trees, spirals, which was not suggested. Several revolutions from the specification to deepen the impression: "aesthetic meaning", "greater satisfaction from the system ownership." Not bad for describing the PC motherboard form factor?

Flex is that he and Flex. The specification is extremely bending, and leaves for the discretion of the manufacturer many things that were previously described were strictly. Thus, the manufacturer will determine the size and placement of the power supply, the design of the I / O card, the transition to new processor technologies to achieve low-profile design. Practically, only dimensions - 9 x 7.5 "" are more or less clearly defined. By the way, about new processor technologies - Intel on IDF demonstrated the system on the FlexATX board with Pentium III, which is still declared only as SLOT-1, and on the photo - see themselves, and in the specification it is emphasized that FlexATX fees only for Socket processors ...

And finally, one more interesting revelation from Intel - three years after three, in the following specifications, the power supply can be found outside the PC housing at all.

And compatibility of the power supply with UPS (uninterruptible power supply).
The ATX Form Factor Standard defines the size, design and other characteristics of the power supply, as well as the allowable voltage deviations during load. We will consider this standard.
At the moment there are such versions of the ATX standard:

ATX 1.3
ATX 2.0
ATX 2.2.
ATX 2.3.

The main differences in the versions of ATX standards are to introduce newer connectors and new nutrition lines. In the first series, the +5 V line was used, and in the second +12 V.

Details about the versions of ATX power supply

One of the main developer of ATX form factor is the company. All documentation is located on the official website of www.formfactors.org, they describe the requirements for manufacturers of motherboards, power supplies and enclosures. Requirements and recommendations for power supplies regulates a document called ATX12V Power Supply Design Guide (PSDG).

The ATX12V standard was released when switching to a new NetBurst architecture. The main innovation in ATX12V, as compared with ATX 1.3, has become a power change from + 12V, and not from + 5V and adding a new 4-pin + 12V power connector (the connector should not be if the maximum possible current of + 12V is less than 10a).

ATX version 1.1 , was introduced in August 2000. For versions 1.0, 1.2, there are no references on the official website, but information about them can be read on other resources.

ATX 1.1 Standard Power Connectors

Version ATX 1.3. released in April 2003. If compared with the previous version 1.1, new current requirements were introduced, the voltage in -5B was removed, the requirements for processing the PS_ON # signal are added, and the reference of the power cable for is added.

ATX 1.3 Power Supply Power Connectors

Version ATX 2.0. compared with the version ATX 1.3, It was significantly changed. First of all, the current energy consumption was increased by + 12V and reduced by +3.3 and + 5V. Standardization of 350W and 400W power supplies (if higher than 300W, 16 AWG wires are recommended). ATX power cable for 24-pin instead of 20-PIN, as well as added +3.3, +5, + 12V, COM (Earth), power supply for devices and power cord.
ATX 24-PIN connector is fully compatible with 20-PIN ATX both mechanically and electrically.

In Version ATX 2.01 and ATX 2.2, standardization of the power supply unit 450W was introduced; Requirements for currents on the lines + 3.3B, + 5V, + 12V are simplified; Improved requirements for efficiency in + 5V Stand BY.

ATX 2.X Standard Power Block Connectors

The most basic power consumers are processors and video cards, the nutrition of which runs along the line in +12 V. If you want to establish the usual processor configuration and the video card (for example: AMD Athlon 3000+ and GeForce 7600 GT), and provide them with power from the block With a capacity of 400 W, then "get skew" voltages. The power line is +12 in wakes up, and the line is +5 in ransortion. And as a result, a self-restart of the computer (or at start-up or during load), blue screens of death, turning off the computer, etc. The problem is that the old power supply blocks the main line is +5 V, and for the processor and the video card you need a line at +12 V, which turned out to be completely overloaded.

ATX (Advanced Technology Extended.) - Form factor for desktop PCs. From the moment of its release, the market that occurred in 2001, this form factor acts as a leading standard in the market of mass-produced form factors for computer systems.

ATX defines the following motherboard parameters:

Motherboard geometry;
Basic requirements for the position of connectors and holes on the housing;
The form and location of some connectors (mainly power connectors);
Geometry sizes of the power supply;
The location of the power supply on the housing;
Electrical power supply parameters;

Dimensions of the board

Name	Board dimensions (mm)





Eatx (Extended)

microbtx.

Ultra ATX



Mini-dtx.

microatx (min.)
Mini-ITX
EPIC. Express
Mini ATX

Nano-ITX
COM EXPRESS.
Esmexpress.

Pico-ITX
PC / 104. *(-Plus)*


mobile-ITX
CoreExpress.

History

ATX Form factor was created and published among computer systems producers in 1995. The author of the development is Intel. The ATX standard acted as a logical alternative and evolutionary replacement for a long time and already an outdated AT standard.

In addition to Intel, and other OEM equipment companies began to actively produce motherboards and power supplies to them (as well as other components) in the new ATX form factor. The global extrusion of the old standard accounted for the end of 1999 - the beginning of 2001. At that time, other modern standards ( microatx, Flexatx, Mini-ITXFor the most part, you have saved the imprint of the key features of the ATX standard, changing only the size of the boards and the number of slots.

In the course of its development, the ATX specification has passed the following evolution of standards:

ATX 1.0 Standard.
ATX 1.1 Standard.
ATX 1.2 Standard.
ATX 1.3 Standard.
ATX 2.0 Standard.
ATX 2.1 Standard.
ATX 2.2 Standard.
ATX 2.3 Standard.

In 2003, Intel was published a new standard called BTX. It was created to increase the level and intensity of cooling the system unit. The ATX replacement was due to the increasing thermal power of the computer components. First of all, it was processors. A new stage of transition to a new format began, which, however, has stopped soon. Most of the representatives of the computer industry abandoned the mass distribution of the new format due to the reduction of power pC components.

To this day, ATX and its derivatives are the most common factors in the market, and in the foreseeable future there is no more interesting alternative to them.

The key differences of ATX from AT

The motherboard is responsible for food processor. To ensure the operation of the control unit, as well as some peripheral devices, a standby voltage of 5 / 3.3 volts is sent to the fee. Despite the fact that in many instructions in order to safely replace components, ultimately require disconnecting the power cord from the outlet, many ATX power supplies are equipped with a tearing switch installed directly on the housing.
The fan located on the rear wall of the power supply can be supplemented or replaced by a 12/14 cm fan, which is installed at the bottom of the power supply. This makes it possible to create a large-volume air flow with smaller turnover, which, accordingly, leads to a decrease in noise level. The location of the elements on the motherboard was carried out in such a way that the processor radiator is installed on the air flow path from the power supply fan.
Power connector has become different. In order to impossible incorrectly connecting two power connectors on each other (as it was in the previous standard), the ATX standard is equipped with a key connector that cannot be connected incorrectly. Due to the increase in power consumed, the number of contacts in the ATX power connector increased at first to 20, and then - to 24.
Received upgrades and back housing panel. The AT standard possessed only a hole for the keyboard connector on the rear panel. Other devices were connected via special boards with connectors installed on the motherboard and attached to special slotted slits. The ATX standard is characterized by the fact that it is located on top of the keyboard connectors (and mouse) by tradition, the rest occupies a rectangular opening of a fixed size, which, depending on the manufacturer of the motherboard, can be filled with various connectors in any arbitrary order. Complete with the motherboard comes a special "plug" with slots for a specific motherboard. It is very convenient because the user appears to appear to use the same case with motherboards equipped with completely different sets of connectors. Also, this "plug" has some other functions: it reduces the emitted Amy and forms a single chassis grounding circuit.

Connectors and plug

The metal "plug", located in the rear of the housing, performs a very important function. Thanks to it, manufacturers of motherboards in the process of integration into their products of various interface devices can be completely free to position the connectors without conducting the coordination of their position with the manufacturers of the housings.

The only discharge requirement is external geometric dimensions:

width: 158.75 ± 2 mm;
height: 44.45 ± 2 mm;
thickness ranging from 0.94 to 1.32 mm;
rounding panel not more than 0.99 mm.

Standard connectors in ATX-case are:

PS / 2. Connector for connecting the keyboard and mouse. On some cases, a universal connector is installed that supports both devices. But now there is a general trend of changing this jack on modern USB -interface. However, among budget cards, these connectors are still used.
3.5 mm connectors (from 3 to 6 pieces) integrated sound card. They include:
- linear output (green);
- line input (blue);
- microphone input (pink);
USB connectors (4 - 8);
Connector for connecting to a local network.

In addition, the following connectors can be installed:

Parallel communication port;
Serial port (1-2) - simple 9-pin connector;
Game port for connecting the joystick or synthesizer;
Digital audio outputs (coaxial and / or optical);
Built-in video adapter;
EXIT OF INTEGRATED VIDEO (D-SUB, S-VIDEO, DVI or HDMI);
Second port for integrated network cards;
IEEE 1394 interface;
Connector for wifi antenna;
Fast reboot button Bios..