Micro-ATX vs Mini-ITX vs ATX: What’s the Difference?

Looking for a primer on the different motherboard form-factors? In this post, we’ve highlighted the main differences between mini-ITX, micro-ATX, and standard ATX motherboards.

Should you get a micro-ATX, mini-ITX, or standard ATX motherboard? If you’re looking to build a new computer, one of the most important components you’ll need to purchase is a motherboard. However, not all motherboards are created the same.

Motherboards can vary in features, cost, and size. The main thing that first-time builders struggle with, is knowing what the difference is between motherboard form-factors (or sizes).

In this guide, we’re going to go over what the main differences are between motherboard form-factors. And, that should give you a better idea of which form-factor motherboard is best for you and your build.

Micro-ATX vs Mini-ITX vs ATX: A Size Comparison

The biggest difference between micro-ATX (mATX), mini-ITX, and standard ATX motherboards are their dimensions:

Standard ATX: 12.0″ x 9.6″
Micro-ATX: 9.6″ x 9.6″
Mini-ITX: 6.7″ x 6.7″

As you can see, mATX motherboards are the same width as standard ATX motherboards, but they are a couple of inches shorter. This size advantage for standard ATX motherboards allows them to feature more PCIe lanes. And, that makes them better suited for multi-GPU setups, or for users that want to utilize multiple PCIe devices.

Mini-ITX motherboards, on the other hand, are shorter in both height and width than micro-ATX motherboards. They typically only feature a single PCIe lane. Their advantage, however, is in their smaller size. They are typically compatible with more small form-factor cases than both standard ATX and micro-ATX  motherboards.

Also Read: Which PC Case Size is Best for Your Next Build?

The biggest take away on the sizes of each of these motherboards are that they mostly determine what PC case you can (or cannot) use.

For instance, if you want to build a small form-factor gaming computer, it is highly likely that you will not be able to use a standard ATX motherboard in it. And, in fact, you may not even be able to use a micro-ATX motherboard in it as well.

On the other hand, if you want to go with a larger case, you’ll likely be able to fit any motherboard in it. That is because most medium-to-larger sized cases will accommodate smaller form-factor motherboards. (However, from an aesthetics stand point, you may not want to put a mini-ITX motherboard in a larger case, as your components will look scrunched up in the top left corner of your case.)

But, it is important to note that the opposite is not true and that you typically cannot put standard ATX or mATX motherboards in mini-ITX cases, or standard ATX motherboards in micro-ATX cases.

The Pros and Cons of Each Form-Factor

You might be thinking to yourself… “Why would I want anything other than a standard ATX motherboard and case? Isn’t bigger better?”

And, the answer to that is that there is a time and place for each motherboard form factor. Each of the three most popular form-factors discussed in this article will make more sense than the others in different scenarios.

So, in this section, we’ll go over the pros and cons of each form-factor so that you’ll have a better idea of which one meets your needs the best.

Form	Pros	Cons
ATX	• Better-suited for overclocking • Better for aesthetic purposes • More PCIe lanes • Higher RAM capacity	• More expensive • Won’t fit inside most smaller cases
Micro-ATX	• The least expensive option • Ideal for single-GPU PC builds • Can fit into pretty much any case • Higher RAM capacity than mini-ITX	• Not suitable for multi-GPU setups • Not ideal for extreme overclocking • Typically lack in aesthetics
Mini-ITX	• Best option for smaller cases • Better aesthetics than micro-ATX	• More expensive than micro-ATX • Won’t look right in larger cases • Won’t work for multi-GPU setups • Not ideal for extreme overclocking • Typically, only have two RAM slots

Which Motherboard Form-Factor Should You Choose?

If you have looked over the pros and cons of each of the three most popular motherboard form-factors above, you probably already have a good idea of what motherboard is best for you.

But, if you are still unsure of which motherboard is right for you, let me outline a few common use cases and which motherboard form-factor makes the most sense for them:

1. You want to build a budget-friendly gaming PC

If you want to build a budget-friendly gaming PC, your best bet is to go with a micro-ATX motherboard. The reason being is that, no components are going to have as big of an impact on your in-game performance as will your graphics card, processor, and memory.

And, so the general rule of thumb when building a budget-friendly gaming PC is to allot as much of your budget as is possible to those three components. As a result, you’ll have to sacrifice a bit of quality on your other components (which doesn’t mean that you should buy low-quality components).

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

And, since most budget-minded gamers won’t have the money necessary to drop on the components that are more suited to the features than standard ATX motherboards offer, there should really be no loved lost for users who don’t end up spending extra on ATX boards.

2. You want to build a high-end gaming PC

Whether you’re looking to build a high-end gaming PC that has multiple graphics cards, or you want to overclock your processor and push it to the extreme, or you want a really fancy-looking motherboard as part of a nice color-coordinated build you are doing, you’ll probably want to look at a higher-end standard ATX motherboard.

And, while there are standard ATX motherboards that offer more of the bare minimum in terms of features, if you want a high-end board, you’re likely going to be forced to choose a standard ATX (or even a larger extended ATX) motherboard.

3. You want to build a small form-factor PC

If you want to build a PC that has a smaller footprint, whether because you want it to be mobile, or you prefer a minimalistic design, your best bet will be to go with a smaller mini-ITX or micro-ATX motherboard.

And, obviously, if you want to go as small as possible, mini-ITX motherboards will be your best bet.

Smaller form-factor PCs are usually best-suited for gamers who want a system that is easy to move around (like to take to LAN parties) or for HTPC systems.

Make the Right Motherboard Choice for Your Needs

Hopefully, after reading this guide, you’ll have a better idea on what form-factor motherboard is right for your needs.

If you want specific motherboard recommendations, be sure to check out our motherboard buyer’s guide, as we’ve rated a bunch of the best motherboard options for each motherboard socket.