eATX vs ATX vs mATX vs mITX: Motherboard Comparison

When buying a computer, either as a pre-built unit or as a stand-alone, you will come across a somewhat confusing specification. It will claim that the PC is ATX or micro-ATX without really explaining what this means. Unfortunately, understanding these confusing acronyms is very important when buying a computer.

While the wrong PC won’t be a disaster for you, it could potentially hinder your future plans with the PC. What do these strange terms mean? Here we go through eATX vs ATX vs mATX vs mITX and cover everything you need to know.

Mainboard Sizes: mITX, mATX, ATX and eATX

Motherboard sizes are referred to as form factors. This can be confusing if you don’t know what they mean. In this section, we’ll look at each motherboard size and the difference between each form factor.

eATX vs ATX vs mATX vs mITX

eATX Motherboards

Let’s start with the largest form factor: e-ATX. If case space isn’t an issue, but maximum performance, features, and reliability are important, e-ATX is for you. This is because the highest quality capacitors and semiconductors are used.

The e stands for extended, which means that these motherboards belong to the category Extended Advanced Technology Extended. They have a dimension of 12 inches x 13 inches. eATX motherboards take up a lot of space in the case.

Generally, e-ATX boards are used for high-performance workstations and servers, but also high-end gaming builds. While they are the same length as ATX mainboards, they are wider. This extra space is generally used for the following:

  • A second CPU
  • e-ATX motherboards usually have eight RAM slots
  • Space for up to eight PCIe slots (some use an older 64-bit PCI standard called PCI-X)

While you can usually use the same processors on an eATX as you can on an ATX motherboard, you can’t always use a PCIe card in a PCI-X slot without seriously affecting system performance.

The I/O panel between ATX and eATX is identical. Many who build a system with an e-ATX motherboard opt for a big-tower case. However, many mid-tower cases can be modified to fit eATX motherboards, although it will likely be a tight fit and cable management can be difficult.

ATX Motherboards

The most popular standard for gaming PCs is ATX, which stands for Advanced Technology Extended. Most ATX motherboards will come with up to 7 PCIe slots. These are needed for graphics cards, sound cards, NVMe PCIe SSDs and various peripherals. In addition, the most common models offer up to four RAM slots and are generally housed in midi-tower cases.

micro-ATX Motherboards

mATX motherboards (micro-ATX) have the same width as standard ATX motherboards, but are a little bit shorter (9.6 inches x 9.6 inches). This length disadvantage ensures that you often only get 1-2 PCIe slots with micro-ATX.

Thus, micro-ATX mainboards are not suitable for multi-GPU setups or for users who want to use multiple PCIe slots. However, you get everything else here that you get with ATX. Often, m-ATX boards are the best solution for gamers, especially since the ratio between features, space and price is perfect.

mini-ITX Motherboards

If you need a PC that is very small and compact, then you should look at the mini-ITX format. This motherboard size is mainly used for extremely compact systems where the entire computer needs to fit in a closet or bookshelf, or be very light and portable.

Typical applications are home theater PCs (HTPCs) where low power consumption means less noise, or LAN PCs that need to be very easy to transport. Many new CPUs have integrated graphics chips, so you don’t even need a dedicated graphics card if you’re not aiming for high resolution or high frame rates.

Especially since the mini-ITX standard only allows for one PCI expansion slot, CPUs with integrated graphics units are also a very practical solution for this. To take full advantage of the smaller form factor, you’ll often need to look for something other than a standard ATX PSU, as these are generally too large for small mini-ITX cases.

You are also limited in your RAM capacity since mini-ITX motherboards only have two slots.

eATX vs ATX vs mATX vs mITX: How do they differ?

Case Size

For one, you can have a smaller computer overall with a smaller motherboard. If you take a look inside a PC case, you’ll notice that much of the height is taken up by the motherboard alone. If you want a smaller computer, it’s a good idea to start with a smaller motherboard!

micro-ATX and mini-ITX are the choice for people who want smaller computers. Small PCs are great if you want something that is portable or doesn’t take up much space as a server or media center. Keep in mind that components designed for ATX computers may not fit in a smaller case.

Periodically, a case designed for a specific form factor may also support smaller cases. ATX cases, for example, are often designed to accommodate micro-ATX and/or mini-ITX motherboards. Be sure to check the manufacturer’s specifications before purchasing a PC case that is a different size than your motherboard.


However, the smaller size comes at a price. Smaller motherboards are made possible by removing expansion slots on the motherboard itself. The result is a motherboard that fits into smaller cases, but doesn’t offer the upgrade freedom that the larger form factors do.

By switching from ATX to micro-ATX, you lose some of the peripheral components interconnect PCIe slots that you plug your graphics card into, for example. ATX motherboards have up to seven PCIe slots, while micro-ATX comes with about three. This means less room for add-ons like graphics, sound and network cards. mini-ITX boards usually only have one PCIe slot.

Sometimes there is also a reduction in RAM slots. ATX to micro-ATX can be reduced from four slots to two, although this is not always the case. mini-ITX often comes with only two RAM slots, although some have managed four. USB ports can also take a hit due to the smaller board.

The opposite is true, of course: the larger eATX boards will have more functionality. At the very least, they usually have four or more PCIe x16 slots, making them a good choice if you have big plans for your PCIe ports. In short, if you’re looking for a PC with lots of ports and upgrade options, stick with ATX or EATX over the smaller options.


While not always the case, micro-ATX computers and motherboards are usually the cheapest option. If you’re looking for a PC where you have no interest in upgrading or installing additional hardware, you may be able to save some money by opting for a smaller motherboard. Just make sure you don’t want to add any additional components in the future, or you may end up buying ATX later to meet your needs.

Advantages and Disadvantages of Motherboard Sizes

Why would I want anything other than a standard ATX motherboard and case? Isn’t bigger better? The answer to this is that there is an optimal application for each motherboard form factor for different scenarios. In this section, we’ll go over the pros and cons of each form factor so you have a better idea of which one best suits your needs.

Format Size (in inches) Pros Cons
eATX 12 × 13
  • Enthusiast overclocking
  • Most PCIe slots
  • Highest RAM capacity
  • Ideal for multi-GPU builds, servers and high-end workstations
  • Often best capacitors and semiconductors
  • Extremely expensive
  • Needs a lot of space and a large case
ATX 12 × 9.6
  • Excellent overclocking potential
  • Easy to find compatible components
  • Often best optics
  • Expensive
  • Requires sufficient space
micro-ATX 9.6 × 9.6
  • Often very affordable
  • Space saving an more mobil
  • Neat overclocking
  • Sometimes less RAM capacity than ATX
  • Often less PCIe slots than ATX
  • Not optimal for extreme overclocking
  • Not suitable for multi-GPU
mini-ITX 6.7 × 6.7
  • Very space saving and compact
  • Optimal for portable HT-PCs
  • Only 2 RAM slots
  • Only 1 PCIe
  • Often quite expensive
  • Limited when overclocking
  • Very limited in GPU and cooler size
Comparison of motherboard sizes

As you can see from the table above, all motherboard sizes have advantages and disadvantages that are relevant to a particular area.

  • mini-ITX is only suitable for small PC builds and is not the first choice if you want to build something more powerful or versatile
  • micro-ATX is clearly the best all-rounder, as these boards are both smaller than ATX and have decent RAM capacity and PCIe slots
  • ATX is top for those who want to build a PC that can handle any scenario
  • e-ATX is for special use cases

What Motherboard size should I choose?

If you’ve looked at the pros and cons over here, then you probably already have some idea of which form factor is best for you. However, if you’re still not sure, we’ll outline some common use cases for you here.

You want to build a Cheap Gaming PC

If you don’t have much of a budget, then it’s best to get a micro-ATX mainboard. The reason for this is that no component affects in-game performance as much as your graphics card, processor, and RAM.

Therefore, the general rule of thumb when building i.e. a cheap gaming PC for Minecraft is to allocate as much budget as possible to these three components. As a result, you’ll have to sacrifice some budget for your other components.

Fortunately, mATX motherboards are perfect for budget gaming PCs, as they still offer all the main features of standard ATX motherboards. The only real difference is that standard ATX usually offers better aesthetics, more PCIe slots, and better VRMs for overclocking.

You want to build a High-End Gaming PC

Whether you want to build a high-end gaming PC with multiple graphics cards, overclock your CPU and push it to the max, or a really fancy motherboard as part of a nice color scheme, the ATX form factor is the first choice for that.

While there are standard ATX motherboards that already offer more than enough features, in some extreme scenarios, some of you will only be happy with an e-ATX motherboard. However, an e-ATX really only makes sense if you have something very special in mind for the system.

You want to build a Very Small PC

If you want to build a PC with a smaller footprint (for a very mobile computer or minimalistic design) it is best to use a smaller mini-ITX or micro-ATX motherboard. mini-ITX motherboards are the best choice if you want everything as small as possible.

Final Words: eATX vs ATX vs mATX vs mITX

The form factor of a PC can be a confusing topic. Now you know their main differences between eATX, ATX mATX and mITX, how they are used and which one suits you best.

Regardless of the use case, we recommend micro-ATX. The only scenario where micro-ATX would not be the first choice would be if you want a large number of PCIe outputs. Also, if you want to overclock heavily or just want something that adds to the overall aesthetic of the build, you’ll probably turn to ATX.


Are smaller Motherboards slower?

Despite their size, smaller motherboards should not run slower than larger ones. Of course, when you go smaller, you have to sacrifice PCIe and RAM slots, which means the potential performance of the computer is less than its larger companion. You may also find that smaller boards don’t handle overclocking and high-end usage as well as ATX and eATX motherboards. However, in terms of smaller boards being inherently slower, they shouldn’t be.