ATX, Micro ATX, And Mini ITX Explained

ATX, Micro ATX, And Mini ITX Explained.

The motherboard kind issue is an important specification that dictates the bodily dimension, mounting holes, and case/energy provide compatibility. It ensures all of your {hardware} elements are completely aligned along with your wants.

Today, most producers adhere to the ATX commonplace, which has made PC constructing and upgrading a breeze for lovers. However, non-standard or proprietary kind elements additionally exist, which cater to distinctive consumer calls for.

Most customers go for the ATX commonplace. Amongst all, these are the preferred ones – full-size ATX, Micro-ATX, EATX, and Mini-ITX.

But don’t fear! I’m not going to restrict this text to simply these 4 motherboard sizes. For your consolation, I’ve categorized all the shape elements into their respective households. This ought to enable you to higher perceive their use circumstances and compatibility.

ATX Family

Let’s start with Advanced Technology eXtended (ATX). This is the preferred kind consider at this time’s date. Developed by Intel, there are a plethora of sizes, every catering to the wants of various customers.

ATX has outmoded the older designs (XT, AT, Baby-AT, and LPX) and has turn out to be the ‘de facto standard’. But that doesn’t imply they’re backward suitable with any of the talked about kind elements.

It has include a number of revisions, the most recent one being the ATX 3.0. Each model has improved by way of energy supply, spike dealing with, and so on.

Whether you’re trying to construct a robust, enthusiastic, high-end, low-end, and even server system, this household integrates every kind. Amongst all, these are the preferred variations – commonplace ATX, microATX, and Extended ATX.

Before we transfer on to the respective headings, right here’s a abstract of the commonest varieties used at this time and the way they differ.

Form Factor Dimension (in mm) Case Compatibility Max. Expansion Slots Max. variety of DIMM Slots No. of mounting holes (max.) Best For
ATX 305 × 244 Full-tower and mid-tower 7 4 9 Standard desktop use
Micro-ATX 244 x 244 Full-tower, mid-tower, and micro-ATX  4 2 9 Budget construct
EATX No fastened commonplace (max-width = 330 mm) Full tower or EATX 7 8 10 Server and workstations
General specs for ATX kind elements

Standard ATX

When somebody refers to ATX, it often signifies the commonplace model. It has an oblong design, measuring 305 mm in size and 244 mm in width. The demonstration of GIGABYTE B450 AORUS ELITE beneath ought to provide you with a greater perception into its measurement.

standard atx motherboard dimension

While that is the full-sized variant, even a mini-sized model was launched (284 mm × 208 mm). Unfortunately, it by no means grew to become a typical and was fully eliminated ranging from the ATX 2.1 specification.

You can instantly plug the enlargement playing cards into the a number of obtainable enlargement slots (most of seven as per the specs). However, this fully relies on the producer and chipset used.

Just perceive that the full-sized ATX boards have a comparatively giant house sufficient to accommodate loads of slots and ports. These often embrace 4 DIMM slots, 6 to eight SATA ports, more headers/connectors, bigger heatsink compatibility, and extra options.

Moreover, it consumes as much as 70W of energy and higher-quality VRM designs. So, it is a appropriate alternative for overclocking lovers as properly.

enough head room for expansion cards
When putting in graphics playing cards on ATX motherboards, be certain that you utilize a case that gives sufficient headroom

ATX boards do include a couple of limitations. For instance, in case you’re planning to put in enlargement playing cards, the PC case must have sufficient headroom. Clearly, it isn’t suitable with the small kind issue circumstances.

Its element association led to greater warmth technology, which is the explanation Intel launched BTX kind elements. The latter was certainly higher by way of structural design and cooling. However, it might by no means exchange the ATX kind issue as deliberate.

Micro ATX

The full-sized ATX is already your best option but it surely doesn’t fulfill the wants of these looking for lower-cost mid-end builds. Also, the Mini-ATX by no means met the calls for, and a greater answer was launched – Micro ATX or mATX!

It follows the ATX rules however is comparatively smaller in measurement. All boards are square-shaped with a bodily dimension of 244 mm x 244 mm. Check out my ASUS PRIME B660M-Okay D4 beneath to get a transparent thought of what a microATX board seems to be like.

micro atx motherboard dimension

That stated, these motherboards can simply match into full-tower and mid-tower circumstances (these starting from 12 to 14 inches). Since it adheres to the ATX-standard location of the mounting holes, you shouldn’t face any points.

It integrates a most of 4 I/O bus enlargement slots. Plus makes use of smaller PSU kind elements (not the ATX however solely SFX/TFX). You would possibly count on a big value discount, however even this relies on the producer, chipset, and construct high quality.

Intel has even developed the Flex-ATX specification, whose measurement was nearly 41% smaller than the full-sized ATX ((229 mm × 191mm). These boards got here with a most of 1 enlargement slot (most often, none). But, they have been absolutely suitable with ATX or micro-ATX circumstances.

Extended ATX

The commonplace and micro variations of the ATX household are already widespread. But this undoubtedly wouldn’t suffice the wants of servers and workstations.

Such customers often search a quad-channel reminiscence configuration, a number of graphics playing cards, and even twin processors! If you’re planning for a server system, it’s best to go for the eATX kind issue. This occurs to be the largest and the most costly among the many three.

These motherboards can combine eight DIMM slots, seven enlargement slots, and greater than eight SATA ports.

eatx motherboard dimension trx40

However, there’s no official ‘extended ATX’ commonplace. So, the bodily dimension fully differs primarily based on the motherboard mannequin. Most of those boards have a peak equivalent to straightforward ATX boards and fluctuate primarily on the widths.

But this isn’t at all times the case! Take a have a look at my GIGABYTE TRX40 AORUS MASTER.

This E-ATX board measures 305 mm x 260 mm. Yours may very well be completely different. I extremely advocate visiting your mannequin’s Tech Specs web page to know the precise dimensions.

Well, motherboards adopting Supermicro/ASUS’s eATX commonplace are often 305 mm × 330 mm. Despite that, not one of the fashions share suitable ATX sample screw holes. So, it’s essential be further cautious when selecting a case for this construct.

Other ATX Variations

Some producers, like MSI, Gigabyte, Foxconn, EVGA, and Supermicro have give you their very own proprietary or semi-proprietary requirements. These embrace EE-ATX, Ultra ATX, and XL-ATX

All of the aforementioned observe the ATX commonplace however their boards are comparatively bigger. Also, they’re largely utilized in workstation and server techniques, just like the EATX.

Let’s get into the essential specs of all the opposite ATX variations that I’ve solely briefly defined above.

Form Factor Dimension (in mm) Max. Expansion Slots Use Case/Note
Mini-ATX 284 × 208 (Intel), 150 × 150 (AOpen) 6 Fits into the identical case as ATX and is used for commonplace desktop use
Flex-ATX 229 × 191 3 Mainly used for leisure and equipment techniques, matches properly in flex-ATX/ micro-ATX/ATX circumstances, most of 6 mounting holes (often 4)
EE-ATX 347 × 330 7 Used in multi-GPU techniques
XL-ATX Varies primarily based on producer (EVGA, Gigabyte, MSI) 9 Used in multi-GPU techniques
Ultra ATX 366 × 244 10 For server-based techniques the place a number of GPUs and CPUs are used
Some different ATX variations and their use circumstances

ITX Family

While I’ve coated most kind elements for desktops and server techniques, what in case you want to construct a smaller rig? Catering to those wants, the VIA Technologies Platform Solutions Division launched the ITX kind issue.

Initially, this was proposed to supersede the Flex-ATX board. A design of 215 mm × 191 mm (6% smaller) was proposed. However, a typical ITX model was by no means launched.

Instead, VIA got here up with the mini-ITX design, which can be one of the crucial widespread kind elements at this time. It even rivals the ATX commonplace regardless of its small measurement.

Besides, skinny Mini-ITX, Nano-ITX, and Pico-ITX are additionally abundantly used. Here are the final specs earlier than you proceed with the detailed clarification of every ITX motherboard.

Form Factor Dimension (in mm) No. of DIMM Slots (max) No. of Expansion Slots (max) Use Case
Mini-ITX 170 × 170  2 1 Compact and moveable gaming computer systems
Thin Mini-ITX 170 × 170  2 1 Thin-client PCs
Nano-ITX 120 × 120  2 1 DVRs, automotive PCs, set-top packing containers, media facilities
Pico-ITX 100 × 72 1 1 Mainly utilized in techniques using ARM structure
Mobile-ITX 75 × 45 mm 1 1 Transportation, army, and medical-based embedded techniques
Neo-ITX 170 × 85 × 35 mm 1 1 Embedded techniques
General specs of ITX kind elements

Mini ITX

As the title suggests, it is a small kind issue that comes with the minimal width and depth dimensions – 170 mm × 170 mm. That’s nearly 34% smaller than the Flex-ATX kind issue.

Despite that, the I/O defend stays equivalent, with no function discount, by any means. So, even a small kind issue can typically be higher than the usual ATX motherboards. This fully relies on the motherboard chipset although.

mini-itx dimension

For instance, my ROG STRIX B550I-GAMING motherboard features a USB BIOS Flashback function. But the opposite ASUS fashions (ATX ones) — ROG STRIX B450-F GAMING or PRIME B450-PLUS, don’t combine such a function.

From the above instance, you might need observed that Mini-ITX kind elements are often built-in with an ‘I’ within the chipset title.

To higher handle house, these motherboards are often outfitted with much less variety of I/O ports, DIMM/enlargement slots, and headers. Thanks to its measurement, it may well simply be mounted on any sort of casing.

For higher aesthetics, it’s at all times best to go for the mini-ITX kind issue, however don’t fear it may be suitable with NAS and different SFFs.

mini itx case holding mini itx board
Mini-ITX motherboard in Mini-ITX case

Usually, TFX PSUs are used to energy these motherboards, and future upgrades are fairly troublesome.

Previously, only some variety of Mini-ITX boards have been obtainable, particularly from VIA. But at this time, you will discover all widespread motherboard producers introduce completely different variations of the identical motherboard mannequin. 

For instance, ROG STRIX B450-F GAMING and ROG STRIX B450-I GAMING each use the identical chipset. The distinction is that the previous is an ATX board whereas the latter belongs to the ITX household.

Thin Mini ITX

If you’re trying to construct thin-client PCs, choosing Thin Mini-ITX can be the most effective guess. However, such motherboards are fairly uncommon to seek out. As per my intensive analysis, I’ve solely come throughout ASUS and Gigabyte providing this type issue.

gigabyte motherboard thin mini itx
Thin Mini-ITX Form Factor Gigabyte motherboard

There’s no refined distinction between the 2 by way of dimension. But to undertake a thinner design, the variety of I/O ports is decreased. Also, it makes use of SODIMM slots (identical to within the laptop computer motherboard).

So, do all pocket book computer systems use the Thin Mini ITX boards? Nope.

When it involves laptops, there’s no ‘standard’ kind issue. This fully relies on the mannequin used.

Other Small Form Factors

VIA has additionally launched some more motherboard sizes within the type of Nano-ITX, Pico-ITX, Mobile-ITX, and Neo-ITX. They don’t simply differ by way of dimension but in addition have particular use circumstances.

To lower it brief, Nano-ITX is primarily utilized in media facilities and set-top packing containers. Their bodily dimension is round 120 × 120 mm

Pico-ITX (100 × 72 mm) and Mobile-ITX (75 × 45 mm) are comparatively much less used (solely in embedded techniques).

gigabyte mini pc
Mini PC Example: Gigabyte MZGLKAP

What about Mini PCs? Usually, they’re bought as absolutely assembled techniques and fall below the ‘Nettop’ motherboard sort.

Check the demonstrated image of Gigabyte’s MZGLKAP above. It has a dimension of 112.6 x 119.4 mm, which neither falls below Nano-ITX nor Pico-ITX. But someplace in between.

Likewise, there are different SFF motherboard varieties, like COM, USFF, UCFF, and so on. A preferred instance of UCFF is the Intel Next Unit of Computing (NUC).


These kind elements have been launched by the Server System Infrastructure (SSI) Forum and are adopted by a handful of producers. 

I’ve come throughout a couple of boards from Gigabyte and likewise from ASUS. They are primarily used for dual-processor functions in servers and workstations.

All three specs are suitable with the ATX household and have equivalent mounting holes. However, they’re bigger by way of width. Have a have a look at their fundamental specs to know how they differ:

Form Factor Dimension (in mm) Max. Expansion Slots
CEB (Compact Electronics Bay) 305 × 267 7
MEB (Midrange Electronics Bay) 411 × 330 12
EEB (Enterprise Electronics Bay) 305 × 330 7
TEB (Thin Electronics Bay) 305 × 267 7
General specs of SSI kind elements (CEB, MEB, EEB, and TEB)


Only available in the market since 2015, Mini-STX has been a preferred alternative for constructing small-factor computer systems. Currently, there are a handful of motherboards coming from ASRock with a typical dimension of 140 mm x 147 mm.

Despite its small measurement, Mini-STX boards have the next worth with higher efficiency. ASRock claims the motherboard can save 14% on energy consumption after the alternative of a typical PSU with a DC-In Adapter.

mini stx motherboard asrock
Example: ASRock’s H110M-STX is a Mini-STX Motherboard

Additionally, it affords higher customization, at the very least two M.2 slots, versatile LAN alternative, a minimal of three video ports, and so on. Thus, this may be an efficient answer in case you’re planning to construct a finances and small-sized system.

Legacy and Proprietary Form Factors

Well, the motherboard varieties that I’ve mentioned are simply those which can be widespread in current occasions. Turning back time, loads of sizes have been obtainable that are actually out of date.

I nonetheless bear in mind my first PC (Biostar MB-1333UCG). It was a Baby-AT kind issue with 330 x 218 dimensions.

You may even discover crypto-mining-specific motherboards having a 305 × 203 dimension. These haven’t simply 4 or 5 GPU slots however combine even as much as 20!

Let’s not get into particular particulars or so. Here are a number of the different motherboard varieties which can be/have been used. Even the beneath listing will not be full as there are merely much more.

Form Factor Dimension (in mm) Status/Use Case
XT 216 × 279 Succeeded IBM PC however now out of date (was once the de facto commonplace)
AT 305 × 330 (max) Superseded
Baby-AT 216 × 330 (max) Succeeded AT however was outmoded by ATX
BTX 325 × 267 Planned to exchange ATX however failed (restricted use)
MicroBTX 264 × 267 BTX variant that may assist 4 DIMM slots
DTX 200 × 244 Designed by AMD for small kind issue PCs
ETX 95 × 114 Used for design functions
COM Express (Basic/Compact/Mini) 95 × 125 / 95 × 95 / 55 × 84 Used for embedded functions
LPX 229 × 330 (max) Adopted semi-proprietary design and outmoded by ATX
NLX 203 × 345 (max) For company desktop or mini-tower techniques
UTX 88 × 108 Used in embedded techniques
WTX 355.6 × 425.4 Used in high-end, multiprocessor, a number of laborious disk servers and workstations
SWTX 418 × 330 Proprietary and utilized in 4-socket servers
Some legacy and proprietary kind elements with their dimensions and use circumstances

What Motherboard Form Factor Do I Need?

all form factor comparison
Most Popular Motherboard Form Factors

There’s nothing referred to as the ‘best’ motherboard kind issue. Each measurement serves a particular objective and the selection fully relies on your wants and desire.

As I discussed earlier, the 4 widespread decisions are ATX, Micro ATX, EATX, and Mini-ITX. Go for the usual variant for general-purpose office/house setup. But in case you’re looking for to construct a rig to your server or workstation, EATX can be the most effective.

For finances builds, I extremely advocate Micro-ATX as they are often excellent for each compact and gaming functions. The final one (Mini-ITX) is for individuals who search portability

Note {that a} small kind issue doesn’t imply they’re cheaper. In some circumstances, their price ticket can go even greater than a full-sized ATX motherboard.

However, motherboard measurement isn’t the one factor to contemplate when getting a motherboard. CPU compatibility, chipset, future-proofing, guarantee, aesthetics (often which have RGB), and cooling are another elements to remember.

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