Micro atx board size. Key differences between ATX and AT. Motherboard manual
ATX (Advanced Technology Extended) Is a form factor for desktop PCs. Since its entry into the market in 2001, this form factor has been the leading standard in the market for mass-produced form factors for computer systems.
ATX defines the following parameters of the motherboard:
- Motherboard geometry;
- Basic requirements for the position of connectors and holes on the case;
- The shape and location of some connectors (mainly power connectors);
- Geometry of the dimensions of the power supply;
- The location of the power supply on the case;
- Power supply electrical parameters;
Dimensions of boards
|
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
The ATX form factor was created and made public among computer system manufacturers in 1995. The author of the development is Intel. The ATX standard acted as a logical alternative and evolutionary replacement for the long-used and outdated AT standard.
In addition to Intel, other OEM equipment companies have begun to actively produce motherboards and power supplies for them (as well as other components) in the new ATX form factor. The global replacement of the old standard occurred at the end of 1999 - beginning of 2001. At that time, other modern standards ( microATX, flexATX, mini-ITX), for the most part, retained the imprint key features ATX standard, changing only the size of the boards and the number of slots.
In the course of its development, the ATX specification went through 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 announced a new standard called BTX. It was created with the aim of increasing the level and intensity of cooling the system unit. The ATX replacement was driven by the increasing thermal power of the computer components. First of all, these were processors. A new stage of transition to a new format began, which, however, soon stopped. Most of the representatives of the computer industry abandoned the mass distribution of the new format due to the reduction in power dissipated by PC components.
To this day, ATX and its derivatives are the most common form factors on the market, and in the foreseeable future there is no more interesting alternative to them.
Key differences between ATX and AT
- The motherboard is responsible for powering the processor. To ensure the operation of the control unit, as well as some peripherals, a standby voltage of 5 / 3.3 volts is sent to the board. While many instructions urge you to unplug the power cord for safe component replacement, many ATX power supplies have a disconnect switch installed directly on the chassis.
- The fan located on the back of the PSU can be supplemented or replaced with a 12/14 cm fan that is installed on the bottom of the PSU. This makes it possible to create a large air flow at lower rpm, which accordingly leads to a decrease in the noise level. Arrangement of elements on motherboard implemented in such a way that the processor heatsink is installed in the path of airflow from the power supply fan.
- The power connector has changed. In order to prevent incorrect connection of two power connectors similar to each other (as was the case in the previous standard), the ATX standard is equipped with a keyed connector that cannot be connected incorrectly. Due to the increase in power consumption, the number of pins in the ATX power connector increased first to 20, and then to 24.
- The rear panel of the case also received an upgrade. The AT standard only had a hole for a keyboard connector on the back. Other devices were connected by means of special boards with connectors installed on the motherboard and attached to special slotted slots. The ATX standard differs in that the connectors for the keyboard (and mouse) are traditionally located on the top, the rest of the space is occupied by a rectangular hole of a fixed size, which, depending on the manufacturer of the motherboard, can be filled with various connectors in any order. Together with motherboard a special "plug" with slots for a specific motherboard is supplied. This is very convenient, since the user has the opportunity to use the same case with motherboards equipped with completely different sets of connectors. Also, this "plug" has some other functions: it reduces the radiated EMI and forms a single chassis ground loop.
Connectors and plug
The metal "plug" located at the rear of the case performs very important function... Thanks to it, manufacturers of motherboards, in the process of integrating various interface devices into their products, can quite freely position connectors, without coordinating their position with case manufacturers.
The only requirement for the plug is external geometric dimensions:
- width: 158.75 ± 2 mm;
- height: 44.45 ± 2 mm;
- thickness ranging from 0.94 to 1.32 mm;
- panel rounding no more than 0.99 mm.
Standard connectors in an ATX case are:
- PS / 2 connector for keyboard and mouse. Some chassis have a universal connector that supports both devices. But at present, there is a general tendency to replace this connector with a modern USB interface. However, among budget motherboards, these connectors are still used.
- 3.5 mm connectors (from 3 to 6 pieces) for an integrated sound card. They include:
- line-out (green);
- line input (blue);
- microphone input (pink);
- USB connectors (4 - 8);
- LAN connector.
In addition, the following connectors can be installed:
- Parallel communication port;
- Serial port (1-2) - simple 9-pin connector;
- Game port for connecting a joystick or synthesizer;
- Digital audio outputs (coaxial and / or optical);
- Built-in video adapter;
- Integrated video output (D-sub, S-Video, DVI or HDMI);
- Second port for integrated network cards;
- IEEE 1394 interface;
- WiFi antenna connector;
- BIOS quick reboot button.
Computer technology is evolving. The shape of the devices, their dimensions and specifications... Today we will consider such a concept as a form factor, and its ATX version is the most popular and demanded.
Form factor
To get to the topic of the article, you need to understand the basic concept. Form factor is standardization in relation to IT equipment. With the help of it, you can determine the size of the device, the main technical indicators, the presence of additional parts, their location.
Now, speaking of the form factor, people think of the motherboard. Previously, the term was applied to phone cases, communication equipment and other PC components.
Given that the form factor is a standardized concept, it is referred to as a recommendation parameter. That is, thanks to the index, which denote a certain form factor, it is possible to indicate the required and additional parameters. Developers try to take the standard for granted and follow it when creating the appropriate component.
Variety
The ATX form factor is not the only standard for components. But it is this option that has become in demand for mass production of PCs. The world saw it for the first time in 1995, and Intel became the manufacturer of this architecture. The XT, AT and Baby-AT standards already existed and were implemented by IBM since 1983.
The ATX form factor influenced the emergence of modified standards. Abbreviated formats began to appear, with fewer slots and compact dimensions. By 2005, a processor-optimized mobile standard was developed.
Office computers also began to be equipped with various components of certain standards. Boards began to appear that were used in complex industries. Such modifications of the standard have become known since 2004. ATX form factor reincarnated as SSI CEB, DTX, BTX, etc.
ATX
This form factor became popular in 1995, but has been most widespread since 2001. The standard has become dominant in PC manufacturing. It affects not only the size of the board or other component. ATX dictates the PSU standard, PC cases, the placement of slots and connectors, the shape and location of the slots, the PSU mount and parameters.
Intel has long pondered how the continuation of the AT form factor should be. By 1995, the developers introduced the brand new ATX standard. In addition to this company, other manufacturers who supplied OEM equipment were thinking about changing the outdated standard. After that, the new standard was picked up by those who supplied motherboards and power supplies.
Over the entire period of its existence, 12 specifications have been released. The ATX form factor has standard dimensions: in millimeters - 305 x 244, in inches - 12 x 9.6. Mods that were released under other names were developed based on ATX, but had differences in port placement, overall dimensions, etc.
So, in 2003, Intel wanted to implement BTX. This new standard cooled the PC system unit more efficiently. The developers wanted to slowly remove from the markets ATX, which maintained high heat inside the system unit. But even such a danger as overheating of the entire system did not contribute to successfully changing the format to BTX.
Most manufacturers refused to distribute it, since reducing the power dissipation showed positive results, and in the future it was still possible to achieve good results when cooling the case and without changing the standard. As a result, by 2011 it became clear that there was no need to replace the ATX form factor.
Major changes
Such a successful invention in this area was not worth waiting for. The user has received drastic changes regarding the previous version of AT. The motherboard began to power the processor. Standby power is supplied to it even when it is off. The motherboard provides the functioning of the control unit and some peripheral devices.
It became possible to replace the fan with a larger one and place it at the bottom of the power supply unit. The air flow became more powerful and covered more elements in the system unit. The number of revolutions changed, and, accordingly, the noise. Over time, there has been a trend towards placing the PSU at the bottom of the case.
Nutrition
The change in form factor brought a change in the format of the power connector. This was caused by the fact that in the previous format, two similar connectors were connected to unsupported slots, which caused the system to crash. In the process of increasing power consumption, it was necessary to increase the number of power contacts. The developers started with 20, later there were more of them, and additional connectors appeared.
Interface panel
The interface panel has become freer. Previously, there was a slot for a keyboard, and expansion cards were installed in special holes. The ATX form factor added space for a communicator to the keyboard slot. The free area was occupied by a rectangular "slot" of a standardized size, where the developers placed the necessary slots.
Initial power supply
In addition to the fact that there is an ATX form factor motherboard, you can also find the standard. Since the development of the format lasted for nine years, during this time the developers tried not only to change the connector, but also to make it compatible with the previous forms.
So, initially a connector with 20 power contacts was used. This option was popular before the advent of motherboards with a PCI-Express bus. Then a 24-pin connector appeared. For this option to be supported by previous versions, “bonus” 4 contacts could be removed, and the board would work with twenty.
Processor changes
When new Pentium 4 and Athlon 64 processors began to appear, the standard had to be revised to version 2.0. So, motherboards began to require 12 V for the main bus. The power supply, the ATX form factor of which was also updated to the second version, had to receive an additional connector. So there was an additional connector for another 4 pins.
After that, options with complex contacts began to appear. For example, a 24 + 4 + 6-pin connector has become demanded for motherboards that have received several PCI-E 16x ports. And the 24 + 4 + 4-pin actually had an additional 8-pin connector, which consisted of two 4-pin slots. Thus, it began to be used for motherboards that had high energy consumption.
This decision with the combination of two 4-pin connectors was caused by the fact that the user does not deprive the user of connecting the model to older motherboards. So, one connector was detached from the other, and we got a 24 + 4-pin wire.
Housing
In addition to the motherboard and power supply, the case also has a certain standardization. The ATX form factor in this case is the most modern and is suitable for motherboards of the same format. Such a housing offers easier access to the entire inner periphery. Has excellent ventilation inside. Allows installation of more than one full-size board.
Despite the same names, it is possible to fit a micro-ATX motherboard. We will briefly discuss this standard further.
Compact version
The micro-ATX form factor appeared a little later than the main standard - in 1997. The motherboard of this format is 244 x 244 mm. The variant was developed for processors with the already outdated x86 architecture.
During the development process, it was decided to maintain electrical and mechanical compatibility with the previous standard. As a result, the main differences remain the dimensions of the boards, the number of slots and integrated peripherals. Micro-ATX is marketed with an integrated graphics card, thereby indicating the intended purpose of this standard. PCs with this form factor are suitable for office work and are not designed for gaming projects, since the integrated video card is mediocre.
Other options
In addition to ATX and micro-ATX, there was a mini-ATX form factor, which is nowhere to be found anywhere else. Its dimensions are 284 x 208 mm. FlexATX also appeared, which measured 244 x 190 mm. This modification is flexible and allows the manufacturer to independently solve many problems.
So, he can choose the size and location of the PSU. Participate in changes related to new processor technologies. But even this variant could not “fight” with ATX and remains in the background.
- 1. Interaction between motherboard and processor
- 2. Choosing Socket "a
- 3. Bus frequency
- 4. Chipset
- 5. Manufacturers
- 6. "Gaming" or "non-gaming" board
- 7. Memory
- 8. Board Form Factor
- 9. Number of interfaces and connectors
- 10. Overclocking the processor
The motherboard is the connecting link of all other computer devices, and therefore the question of how to choose the right motherboard is far from idle. The stability of the PC and its durability depend on the choice of the motherboard, and we do not want to find ourselves in a situation of the need for frequent, expensive hardware selections and updates, do we?
In this material, we will tell you what motherboards are, what parameters you should pay attention to in the first place, how to choose a motherboard so that it fits the processor, and so on. First of all, you should ask yourself the question: in which PC the motherboard will be located - office, gaming or with mixed purposes (home).
Interaction between motherboard and processor
First of all, we must decide on the architecture of our future PC, namely, decide on the basis of AMD or Intel, we will build our entire system.
Socket selection
Socket is a type of connector in the motherboard corresponding to the processor connector, it is he who divides all existing boards into two large categories:
- Sockets starting with AM, FM, and S support AMD processors;
- Sockets starting with LGA have support for Intel processors.
Thus, we understand that the choice of a motherboard and a processor must occur simultaneously, and if you plan to use a motherboard for more than one processor generation, you will be forced to remain true to the previous choice of the processor manufacturer. It is also worth noting that a motherboard can be equipped with more than one socket (but of the same type), but such solutions are usually preferred for creating servers, rather than PCs for personal use.
Bus frequency
This paragraph refers to the general bandwidth devices, the higher the frequency - the higher the system performance, everything is obvious here. As a reminder, the processor bus frequency must also match the motherboard bus frequency, otherwise you will be wasting your money. Find the devices that will show the best performance when working in tandem.
Chipset
Everything is simple here, the chipset, also known as the north bridge, is a set of microcircuits contained on the motherboard and acting as a connecting link between connected devices. The most popular manufacturers include the aforementioned AMD and Intel, as well as ATI and NVIDIA, well-known for the production of video cards.
The main modern Intel chipsets include:
- B250 / H270 - for office, multimedia and gaming PCs;
- Q270 - for the corporate sector;
- Z270 - for powerful gaming and professional PCs;
- X99 / X299 - for very powerful professional PCs.
The main modern AMD chipsets include:
- A320 - for office and multimedia PCs;
- B350 - for gaming and professional PCs;
- The X370 is for the enthusiast.
These chipsets have a lot of differences, but in the end we are only interested in their intended use. If we are looking for a motherboard for a gaming computer, then we stop at the Z270 and B350, and so on. Knowing the final purpose of the assembled computer will not be difficult even for a beginner to choose a motherboard.
Manufacturers
This point is important if you decide to choose a motherboard. The most expensive and most relevant in the high price segment are motherboards from ASUS. If we look through the prism of price / quality, especially if we are looking for a motherboard for games, then we should pay attention to the MSI brand. In a more customer-loyal segment, motherboards from Gigabyte and ASRock look good.
There are less eminent manufacturers on the motherboard market and their name is legion, but such fierce battles do not flare up around motherboards as around processors or video cards, and therefore you should not overpay solely for the name, all the more unsuccessful models are found among the headliners of the market. In any case, it is worth remembering that when asked how to choose a motherboard, the answer should not start with the manufacturer's name - it is secondary.
"Gaming" or "non-gaming" board
In fact, the motherboard is not responsible for performance in resource-intensive applications like demanding games, so this concept is very ephemeral. If you insert four strips of RAM into an expensive board and repeat this process with a cheaper one, the result will not change.
Behind appearance have to pay The only difference is the card's potential when overclocking the processor; here you should take a careful look at the board's power supply, cooling, voltage stability during overclocking and other secondary characteristics. In general, a few words will be said about this in the conclusion.
Memory
The number of slots depends on the form factor of the motherboard, so don't expect to fit more than two strips into a compact format motherboard. Full-size motherboards can handle four slots, and sometimes more. The current type of memory at the moment is DDR4, but they also differ in frequency. True, we do not recommend chasing beautiful numbers above 3000 MHz for now, the price growth is exponential, but the performance gain is not so great
These are not all characteristics that distinguish a good board from a weak one, but they will be enough to avoid getting into an unpleasant situation after the purchase.
Board Form Factor
The dimensions of the board directly affect the dimensions of your computer case, and, accordingly, the space that it occupies, so there is no point in taking the largest format - it will not necessarily be the most productive, but it will certainly be the most bulky.
Let's take a closer look at the options available:
E-ATX - size 305x330 mm. These boards are designed for the LGA 2011-3 connector and, as can be seen from the dimensions, can become a headache in terms of ergonomics. They are designed for top-end processors and are equipped with the most efficient cooling and power elements. If the occupied space is not a headache for you, you can safely give them your preference.
Standard-ATX - 305x244mm. Perhaps the most widely presented format on the market, with it you will not have any problems with compatibility with other devices, but, as before, the board is quite bulky and not suitable for compact solutions.
Micro-ATX - 244x244 mm. The reduction in board height is achieved by reducing the PCI-e slots. If earlier this form factor was perceived as a budget analogue of larger motherboards, then with the development of electronics it became able to implement all the functionality of its older brothers.
Mini-iTX - 170 × 170 mm - an option for those who like to replace the standard computer case with something compact and stylized as a multimedia player.
Mini-STX - 140 × 140 mm. It already uses memory modules from external laptops and external power supplies. You can experiment with building a PC based on this board, but most likely you will lose in performance and overpay.
Number of interfaces and connectors
Often buyers choose a board based on the name of the manufacturer or the mythical term "gaming", but when they come home they find that they simply cannot connect a particular device to it. So that such an incident does not happen to you, we will try to briefly review all the external interfaces necessary for the motherboard.
First, you need to decide how many USB outputs you need on the rear panel to connect peripheral devices. Do not chase the number, but a reasonable 4-6 ports should be present. It is advisable that a couple of them comply with the 3.0 standard, then you will not have the hassle of connecting portable hard drives. The 3.1 format is slowly entering our life - it would be nice to look beyond the event horizon and attend to its presence.
SATA is another necessary connector, high-speed SSDs work with this interface, since this connector is an integral part of any, even the most budget motherboard. 
A tip from my own experience - be sure to consider the built-in Wi-Fi adapter. A router is already installed in almost every home and it is much easier to purchase a suitable board than to take the time-consuming process of laying a cable to your computer and spoil the appearance of the room.
If you are an audiophile and sound quality is important to you, pay attention to whether the integrated sound card supports 5.1 and 7.1 systems, or immediately ask to add a suitable discrete sound card to your motherboard.
PCI-express slots and their location are not so critical for gamers who choose one top-end card, but if you are pursuing other goals and want to use SLI / Crossfire technologies, then take a look at the number of ports and the comfort of their location - it will not be superfluous.
Overclocking the processor
If your motherboard is the basis for overclocking the processor, then you need to immediately inquire about the previous experience of the owners of this motherboard in order to achieve maximum results and increase performance as much as possible. If you are looking for an "overlocker" card, do not shy away from reviews from reputable experts. If the same card from time to time shows decent performance in this difficult matter, it is likely that it is the answer to your question of how to choose a motherboard for your computer.
I hope our article on the tricky question of choosing a motherboard helped you, and you will never again become a victim of the cunning of sellers or your own ignorance of the issue. Patience in analyzing the saturated motherboard market and good luck with your purchase.
ATX (Advanced Technology Extended) - a standard created in 1995 that describes the geometric dimensions and methods of their coupling, as well as the geometric and electrical parameters of power supplies, their methods of connecting to motherboards and interacting with them.
A visual comparison of the sizes of motherboards of popular ATX family formats:
A more complete list of known standard sizes of motherboards:
Currently used or planned for use in computers:
| Name | Board size (mm) | Comments: |
| XL-ATX | 345 × 262 (325 × 244) |
XL-ATX. The first representative of this form factor was the Gigabyte GA-890FXA-UD7 motherboard, released on April 1, 2010. XL-ATX cards are longer than standard ATX cards and allow you to create a motherboard with the ability to install up to 10 expansion cards. The length of the motherboard does not allow installing it in cases designed for ATX or E-ATX motherboards, therefore, you must choose special cases. |
| Enhanced E-ATX | 347 × 330 | SuperMicro's proprietary E-ATX expansion. The board is 32 mm wider (from the power supply side) than a standard EATX board, which requires a corresponding case. This format is usually referred to simply as E-ATX (347 × 330) |
| E-ATX | 305 × 330 | Extended ATX. The most popular board and chassis format for dual-processor workstations and servers. Second name SSI EEB |
| SSI CEB | 305 × 267 | Format of motherboards for workstations. Recently, boards of this format have begun to appear for gaming computers. It is possible to install boards of this format in E-ATX cases |
| ATX | 305 × 244 | The most popular (together with MicroATX) motherboard format. In practice, boards can be as short as 305x170 |
| microATX | 244 × 244 | The most popular (together with ATX) motherboard format. In practice, boards can be as short as 244x170 |
| FlexATX | 229 × 191 | A scaled-down version of MicroATX offered by Intel |
| Mini-DTX | 203 × 170 | |
| Mini-ITX | 170 × 170 |
Other motherboard formats not fully ATX compatible.
Obsolete or not widely used:
| Name | Board size (mm) | Comments: |
| WTX | 356 × 425 | Workstation ATX - found, as a rule, only in brand-name four-processor platforms, as well as SWTX close to it |
| AT | 350 × 305 | Original motherboard formats for personal computersproposed by IBM and dominated the market until the late 90s of the XX century. As a rule, most Baby-AT boards can be installed in an ATX case. | Baby-AT | 330 × 216 | DTX | 244 × 203 | Reduced versions of MicroATX from AMD. |
| NLX | 254 × 228 | Original "proprietary" standards of large PC manufacturers. They have been completely superseded by MicroATX. |
| LPX | 330 × 229 | |
| BTX | 325 × 266 | The format, which was developed as a replacement for ATX, but never became it. |
| microBTX | 264 × 267 | |
| Nano-ITX | 120 × 120 | Reduced versions of MicroATX offered by VIA. |
| Pico-ITX | 100 × 72 | |
| mobile-ITX | 60 × 60 | Ultra-compact motherboard format for mobile and embedded computers, also proposed by VIA |
Used in industrial and embedded equipment:
Motherboard form factor - the standard that determines the dimensions of a motherboard for a PC, where it is attached to the case; the location on it of bus interfaces, I / O ports, a CPU socket and slots for random access memory, as well as the type of connector for connecting the power supply. In the latest versions of the form factor, both the requirements for the computer cooling system are determined. When choosing components for a PC, you must remember that the computer case must support the form factor of the motherboard.
ATX form factor (Advanced Technology eXtended) is a form factor that was proposed back in 1995 by Intel and has remained immensely popular since then. ATX form factor motherboards measure 30.5 x 24.4 cm. Currently, most motherboards, chassis and power supplies based on intel processors and AMD come in ATX format.
Features of the ATX specification include the following:
- placement of I / O ports on the system board;
- built-in PS / 2 connector for keyboard and mouse;
- the location of the IDE and FDD connectors is closer to the devices themselves;
- placement of processor sockets in the back of the board, next to the power supply;
- use of a single 20-pin and 24-pin power connectors.
mATX (micro ATX) - reduced ATX standard. It is used primarily in office machines where many configuration slots are not required. The mATX standard measures 24.4 x 24.4 cm and supports 4 expansion slots. The motherboard of the mATX standard has a main connector for connecting a power supply, containing 20 or 24 pins. Almost all new models since 2003 have a 24-pin connector.
EATX (Extended ATX) - the main difference from ATX is the size (30.5 x 33.0 cm). Their main field of application is servers.
BTX (Balanced Technology Extended) - a new standard designed to effectively cool the internal components of the system unit. BTX is relatively small and suitable for building miniature computers. BTX cards are 26.7 x 32.5 cm in size and have 7 expansion slots.
mBTX (micro BTX) - a smaller version of BTX, supporting 4 expansion slots. mBTX - measure 26.7 x 26.4 cm.
mini-ITX - standard electrically and mechanically compatible with ATX form factor. The mini-ITX form factor was developed by VIA Technologies and has a small size (17 x 17 cm).
SSI EEB (Server Standards Infrastructure Entry Electronics Bay) - this form factor of the motherboard is mainly used for building servers and has dimensions of 30.5 x 33.0 cm. The main connector for connecting the power supply has 24 + 8 pins.
SSI CEB (SSI Compact Electronics Bay) - this form factor is also used for building servers and has a 24 + 8 pins main connector. The dimensions of such boards are 30.5 x 25.9 cm.
Outdated standards: Baby-AT; Mini-ATX; full-size AT board; LPX.
Modern standards: ATX; microATX; Flex-ATX; NLX; WTX, CEB.
Implemented standards: Mini-ITX and Nano-ITX; Pico-ITX; BTX, MicroBTX and PicoBTX
