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

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

The market is going to offer you a sea of motherboards to choose from. This is a good thing because having a choice means that you can just pick the right motherboard and be on your merry way. However, for a lot of people, especially newcomers, this is not the easiest thing to do as there are some complications that can come in the way, one of them being the size of the motherboard.

Now, suppose I am looking for the best motherboard for Ryzen 5 5600X, and I am presented with three different sizes—ATX, micro-ATX, and mini-ITX. What would I go with? Well, I know the answer but if you are someone who is just getting into building a PC, you might find yourself confused, and that is why, we are going to take a look at the difference between these motherboards and whether or not it matters.

Understanding Motherboard Form Factor

It would be perfectly okay for me to just end this article by telling you tha the ATX is the largest of all three form factors but that would not be the right way. You need to understand that motherboard form factors go beyond ATX, as well.

The smallest being mini-ITX, we then move to micro-ATX, ATX, E-ATX, and XL-ATX. However, these are just the consumer grade motherboards. There are commercial level offerings that are even larger but we are not going to talk about them in this article.

So, do you really get by going for a bigger or a smaller motherboard? Well, ATX motherboards are the standard now, having ample SATA ports, NVMe slots, PCIe slots, and plenty of USB ports on the back.

So, when comparing different sized motherboards, the one thing to keep in mind is that the smallest mini-ITX will have the least number of slots. They are great for HTPC builds or builds that don’t require a lot of expansion slots, in the first place. They are also more expensive than some of the other offerings, and contrary to popular belief, they can be used for overclocking and other high-end applications provided you are going for the appropriate motherboard in the said series.

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

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

Okay, now that we are done making sure that you know what motherboard form factors are, let’s make it simpler for you by talking about some of the differences found in these form factors. So you can have a better understanding. Below is a small table that will help you understand the key differences.

Dimensions12”x9.6”/305mm x 244mm11.2”x8.2”/284mm x 208mm6.7”x6.7”/170mmx170mm
RAM Slots2 or 42 or 42
PCIe SlotsUp to 7Up to 41

You can clearly see the difference in RAM slots and PCIe slots. However, there are few things that I have omitted from this table. For instance, the number of SATA ports and I/O on the back. The reason being simple that these ports vary from motherboard to motherboard. So, there is no exact way to have a proper representation.

Now, another really important thing to note here is that whether you are going for a mini-ITX motherboard or a full sized ATX motherboard, the price difference can be alarming. Smaller motherboards, especially the higher end offerings are more expensive than their larger counterparts, so that is one thing that you must keep in mind when looking to get a new motherboard. They are also not as common, so you have to be sure that you are picking the right fit.

The last tip that I will give to you is that whatever motherboard you are looking for, be sure that the size corresponds with the size that your case supports. If your case supports ATX, it will also support smaller motherboards but that will leave a noticeable gap or empty space. However, it cannot be the opposite—if your case supports only mini-ITX motherboards, then it will only be able to house the said motherboard.


Finding the right motherboard should not be an issue for anyone. The aim of this post is to make it clear to everyone that whenever you are in the market looking for a good motherboard, the offerings are all there and you just have to be careful in picking the right offering or things can easily go wrong or out of the way.

Rest assured, as far as the size is concerned, all sizes are good and have their own purpose. It all boils down to what your preference is and what you plan on doing with the build.