What is the difference between ATX and Micro ATX?

This comparison between Micro ATX and ATX aims to clarify which motherboard type is the right choice for our PC configuration. So, we compare them to know their differences.

mATX has always been said to be cheaper, less flashy, less choice motherboards and “ugly” in a big mid-tower. The thing is, manufacturers have greatly improved this form factor, so it’s not unreasonable to consider a Micro ATX before an ATX.

What is Micro ATX?


Known as mATX or MicroATX, it is a smaller form factor than ATX, measuring 244 x 244 mm. They are characterized by having 4-2 RAM memory slots, a maximum of 2 PCI-Express x16 slots and 1 M.2 slot (although there are 2 models).

It’s the next step when we start with mini-ITX, and since the most basic models are usually mATX, it has always been considered an economical or “low cost” form factor. However, regardless of what factor it has, this cheaper model is usually a very basic one.

We say this because if we go to the higher ranges we will see that there are some pretty good Micro ATX motherboards and they are sometimes better than the lower priced ATX model. Ultimately, everything is summed up in the ranges we evaluate.

Uses of Micro ATX

For those who don’t want to complicate their lives or spend a lot of money on components, the Micro ATX form factor is extremely useful. We have everything we need, something we cannot guarantee in the Mini-ITX form factor as it is much more limited.

But Micro ATX is a reduced option of ATX (as the name suggests), so you can overclock, mount a powerful GPU, have a good cooler or AIO kit, equip dual-channel RAM memories, and even have an M.2 SSD installed. We can have .

I think I would recommend Micro ATX to people who:

  • Those who do not want to have a large computer case.
  • Those who have a tighter budget and want good performance.
  • Those who prefer to invest more money in other components.
  • Those who don’t care too much about aesthetics because many Micro ATXs look a bit ugly than ATX cases.
  • Those who want to enjoy a normal configuration at a reasonable price.
  • Those who want to build a small PC.

What is ATX?


This form factor doesn’t need much explanation because it’s most common on motherboards. It’s been with us since it was released by Intel in 1995. They are characterized by having dimensions of 305 x 244 mm, larger than Micro ATX. However, the E-ATX (Extended ATX) are the largest motherboards on the market, although their offerings are geared towards overclockers only.

They are the most common for a fundamental reason: they are the ideal size to equip with the necessary parts. It will depend on the range, but normally, we have one PCIe x16 slot and another PCIe x8 and 2-3 others using 4 or 2 rails.

As for the RAM slots, they all come with 4 slots because they are the most used and no more is needed. In the case of E-ATX, a configuration only seen in the professional sector, we see 8 slots.

Uses of ATX

Being a very common form factor, we find different receiver profiles as it is found in all possible ranges: entry-level, mainstream and overclocker. Therefore, it can be said that their uses vary.

However, it would be helpful to know what benefits there are for us by opting for an ATX over a Micro ATX:

  • They provide good cooling through the space between components. In Micro ATX all components are closer together, so heat builds up along the motherboard.
  • They offer more M.2 slots. If we only want to mount M.2 SSDs in our configuration, the ideal form factor for the price-performance ratio is ATX. You will find 2 M.2 slots on any generic ATX motherboard.
  • Overclock is more interesting. The fact of having more space allows the manufacturer to install more and higher quality VRMs, which is very good for CPU overclocking: the motherboard will be cooler.
  • Liquid cooled models. As we scale up the range, we’re seeing models with waterblocks that clearly make it a common form factor among overclockers.
  • More PCI-Express slots. Normally 1 or 2 is used at most, but sound card, GPU etc. There are people who take advantage of them. Whoever uses these slots will definitely prefer ATX.
  • More product variety. Although they are slightly more expensive than the Micro ATX in the same range, we have a lot to choose from. This is because manufacturers are focusing the Micro ATX on the entry-level range, placing some models in the mainstream and a very few models in the high end.

ATX – Micro ATX, which one to choose?

We’ve looked through every form factor, but which one to choose? Here are my conclusions from this comparison between ATX and Micro ATX:

  • Catalogue: There are more ATX models than Micro ATX, but it’s true that there are more Micro ATXs in the lower price ranges.
  • If you’re looking for something cost-effective, choose Micro ATX.
  • A Micro ATX motherboard has everything we look for in a motherboard.
  • In the case of overclocking, ATX is more convenient.
  • ATX is more suitable for cooling.

Therefore, my choice is in favor of ATX in case we are more demanding on our PC. If we are not going to overclock neither the RAM nor the CPU, we will only use the PCI-Express slot and we have no high pretensions, choose the cheapest for you.