When looking into buying a new mobo, motherboard sizes are one of the first things we come across. Some of the most popular options are Mini ITX, M-ATX, and Standard ATX. 

The question is, does size really matter? Why should we go with something bigger and more expensive when there are more compact options on a budget? 

This article is made to answer all these questions and so much more than that. So, if you want to learn more, then keep on reading!

Motherboard Sizes

As far as motherboard sizes are concerned, there are quite a lot of options out there. However, the most popular options that are targeted towards both consumers and/or enthusiasts are: 

  1. Mini-ITX
  2. Micro ATX (Also widely known as M-ATX and m-ATX)
  3. ATX
  4. E-ATX

Mini-ATX is the smallest size while E-ATX is the largest. There are also a few other options that are ultra-compact and others that are made to host dual CPUs. But, that’s a topic for another time. 

For now, we’re only going to focus on the Mini-ATX, M-ATX, Standard ATX, and E-ATX offerings. 

Mini-ITX

This is by far the smallest motherboard that you can get – at least as far as the most common options are concerned. 

Do keep in mind that smaller does not necessarily mean cheaper. Especially if you’re looking into gaming mobos. 

One of the reasons that you can find a ton of expensive Mini-ATX motherboards is because of things like decent VRMs, chipsets, fast RAM support, and things like that which will cost money regardless of the motherboard size. 

That being said, Mini-ITX mobos can be the cheapest of the bunch. But that’s only because they sacrifice a few features such as DIMM slots, PCI-E slots, and SATA slots. 

Overall, when it comes to Mini-ITX offerings, you basically sacrifice a few slots in order to save space and maybe money – depending on what you’re after.

Still, if all you need is a budget to mid-range build, a compact motherboard should be enough. Sometimes, even for high-end, small builds. After all, 2 DIMM slots are more than enough to fit 16 gigs of memory and a single PCI-E slot is all we need for a high-end GPU. 

Just do keep in mind that the smaller that your case and motherboard are, the higher the temperatures will be. After all, PC components generate heat and they need a bit of room to breathe. 

One good thing about Mini-ITX mobos is that they can fit in pretty much any case. After all, most standard ATX cases can support both Mini-ATX and Micro ATX motherboards as well. 

Pros: 

  • Very small
  • Generally cheaper than the bigger options
  • Can fit in most cases

Cons: 

  • Bad thermals 
  • Limited functionality

Micro ATX

These motherboards are slightly smaller than standard ATX mobos while still offering quite a lot of functionality. Most of them tend to be cheaper than their larger siblings. Especially the ones that only come with 2 DIMM slots. 

Compared to Mini ITX, a Micro ATX motherboard gives you quite a lot of room to play and that results in lower temperatures and more features as well. 

For example, while there are a lot of compact motherboards that only offer a single PCI-E slot and maybe a couple of SATA slots, most Micro ATX offerings have at least a couple of PCI-E slots, 4 SATA slots, and sometimes even aν extra PCI 1x slot.

Since Micro ATX is smaller than standard ATX, most ATX cases will allow you to install a Micro ATX motherboard as well. 

Overall, buying a Micro ATX motherboard means that you’re getting something close to a standard ATX size that’s slightly smaller and works with most cases out there. Most of the time, you can find them at a smaller price point as well. Not a bad bargain indeed.

Pros: 

  • Decent features
  • Smaller than ATX
  • Good value (Usually)

Cons: 

  • Still not as good as ATX in terms of features and functionality

ATX

This is the de lingua franca of motherboards. ATX has been the standard motherboard form factor for quite some time now and that’s what your average builder prefers. 

ATX motherboards are slightly larger than their Micro ATX siblings and much larger than the compact Mini ITX offerings. So, if you’re on the lookout for a compact build, you can basically forget about ATX mobos.

Still, that extra space gives the components some breathing room – which results in better thermals, and also quite a bit of extra functionality. 

You can generally expect to find 4-6 SATA slots, at least a couple of PCI-E 16x slots, 2 PCI 1x slots, more USB connectors on the back, more fan headers, and more USB case connectors as well. 

That’s why ATX motherboards are the most popular option in terms of motherboard sizes. They can be used to build anything from a budget PC all the way to a high-end gaming workstation. 

Their only downside is their size. Since they are larger than everything that we’ve mentioned till now, you can only really fit them on ATX cases. 

That greatly limits the buying options and it can also be a deal-breaker for those who want something smaller. 

Pros: 

  • Tons of features and functionality
  • Offers a lot of flexibility (Can be used for both budget and high-end builds)
  • Great thermals

Cons: 

  • Bigger in terms of size
  • Generally a bit more expensive than the smaller options

E-ATX

This is not your average motherboard. E-ATX mobos are generally targeted towards enthusiasts and server builders. 

They are slightly larger than their standard ATX variants – which means that they also need a case that offers E-ATX support. Do keep that in mind because some ATX cases also offer support for E-ATX mobos. But, definitely not all of them. 

That extra space is useful for adding more DIMM slots (Usually 6-8), more PCI-E 16X slots, and more SATA slots as well. And this is why they are so popular with both enthusiasts and server builders. 

The extra DIMM and SATA slots are useful for extra drives and memory for servers while the extra GPU connectors are great for multiple GPU setups. Yes, we know that Crossfire and SLI support is kind of dead at this point. But, to each their own. 

Overall, if you’re an enthusiast or someone who is looking into building a small server, consider checking out some E-ATX motherboards. Because, other than that, E-ATX offerings aren’t all that better compared to the standard ATX form factor. 

Pros: 

  • Offers more features and functionality than you’ll ever need
  • Slightly better thermals compared to ATX (Due to the slightly increased size)

Cons: 

  • Largest option 
  • Generally more expensive

Wrapping Up

That’s all for now. As far as common motherboard sizes are concerned, that was all you need to know. 

If all of that information feels a bit overwhelming, here’s everything that we talked about in a nutshell :

  1. Mini-ITX: This is the smallest variant and it’s compatible with most cases out there – but it also sacrifices various slots and ports in order to achieve that. 
  2. Micro ATX: Noticeably larger than Mini-ITX and slightly smaller than standard ATX. Fits in most ATX cases as well and most options offer a decent number of ports 
  3. ATX: Standard size. Offers pretty much everything that your average person is going to need
  4. E-ATX: Largest variant. This one is mainly made for enthusiasts and server builders as your average person is never going to need 8 DIMM slots and 4 PCI-E 16 slots