ATX vs Micro vs ITX – Differences & Uses

Motherboard form factor

Standard ATX, Micro ATX, & Mini ITX are the most popular form factor among PC builders. Beginners would often wonder what the differences are, and what’s the best. It’s not just size that separates these motherboards.

They differ regarding size & compatibility mostly, but they have slight differences that make a large difference.

The motherboard is one of the most important parts of your build. It dictates Expandability, Compatibility, and the overall size of the system. When choosing a form factor, you must have your intentions in mind.

Form Factors Come In Different Sizes

The most obvious difference is the difference in size, Standard ATX being the largest, and Mini ITX is the smallest.

ATX vs Micro Vs ITX form factors
Motherboard form factors Courtesy Of VIA GALLERY.
Form FactorDimensions(length x width)Supported Cases Screw holes
Extended-ATX305 x 330 mmEATX Cases
Standard-ATX305 x 244 mmFull/Mid ATX Cases
Micro-ATX244 X 244 mmFull/Mid/Micro ATX Cases
Mini-ITX150 x 150 mmFull/Mid/Micro/Mini ATX Cases

In this table, you can tell that the smaller motherboards are compatible with the larger form factor cases. This is because of the screw holes. Micro ATX and Mini ITX screw holes are a subset of the full-sized ATX boards.

So that means you can use a Mini ITX board in a Full tower PC case, but it does sound pointless doing that because your case’s upgradability will be bottlenecked by the motherboard.

Your choice of form factor will determine which case you will be using. Keep in mind, if you go for Standard ATX, you may not be able to use cases smaller than a Mid Tower.

Larger Form Factors Have More Upgradability

We can see a trend, the larger the motherboard, the more slots it has. Micro and Standard ATX motherboards share the same width, but standard ATX motherboard is longer in length.

The height advantage of the standard ATX motherboard allows for more PCI-E slots resulting in more upgrade potential.

PCI-E Limitations With Smaller Form Factors

The problem with smaller form factors is that they’re extremely limited with PCI-E slots. It the price you pay for portability & compactness.

The Mini ITX motherboard only has 1 PCI-E slot, you will likely be installing a graphics card here, but there is no hope for installing other PCI-E devices.

If you have thoughts about installing extra PCI-E cards like Sound cards and Wifi Cards, then you will need a Micro ATX motherboard or larger.

Mini ITX builds are niche builds with very specific intentions. If you’re thinking about running multiple graphics cards, with a ton of RAM, then Mini-ITX definitely isn’t for you.

Form FactorPCI-E Slots
Standard ATXUp To 6
Micro ATXUp To 4

RAM Upgradability

ram slot form factor

Standard and Micro ATX Motherboards both support up to 4 RAM sticks, whereas Mini ATX can only support up to 2. The max capacity of a Mini ATX motherboard is 2×16 which is 32GB of memory.

Standard and Micro ATX can support up to twice that capacity. 32GB of RAM is more than enough, but just in case you need that extra capacity, Standard & Micro ATX can give you that extra capacity.

Form FactorMemory Slots
Standard-ATXUp To 4 Memory Slots
Micro-ATXUp To 4 Memory Slots
Mini-ITXMAX 2 Memory Slots

Smaller Form Factors Are More Portable

A smaller motherboard means you can fit it inside a tiny, compact case. That is one of the many benefits of going for Mini or even Micro ATX.

Micro ATX has the benefit of being a balance between both Standard and mini ITX motherboards. It retains upgradability whilst also offering portability.

Mini ITX motherboards can become so compact that you can hold them with one hand. You can build such a tiny PC with the same power as a standard ATX motherboard. This is attractive to a lot of people, especially gamers.

Pros And Cons For Each Motherboard Form Factor

Keep in mind, preferences vary from person. No motherboard is better than the other. Someone may have a specific reason to build a Mini-ITX build, it doesn’t make it better than a standard ATX motherboard.

Standard ATX Motherboard – Pros & Cons

  • Standard ATX has the most upgradability
  • Supports up to 4 memory slots
  • Supports up to 6 PCI-E slots
  • Better airflow & cooling
  • Large, Least portability
  • Cannot fit in cases smaller than a Mid Tower
  • Standard ATX builds definitely have the most upgradability out of the three. With up to 6 PCI-E Slots, you are able to install extra PCI-E cards such as sound, and wifi cards.
  • 4 memory slots are great if you’re going to fill them all up. You have the ability to use up to 64GB RAM.
  • When using a standard ATX motherboard you’re going to be using a larger case. With that being said, the airflow will be excellent. Extreme overclocking is possible with such a build.
  • However, standard ATX comes with a price. You won’t be moving this build around a lot due to the size.
  • Also, you cannot fit a standard ATX motherboard into a case smaller than a mid-tower. You cannot have both compactness and upgradability

Micro ATX Motherboard – Pros & Cons

  • Micro ATX boards are budget-friendly
  • Can fit in a large variety of cases
  • Same RAM capacity as Standard-ATX being 4 slots
  • Compact to a certain extent
  • Fewer PCI-E slots than Standard ATX
  • Extreme overclocking may be an issue
  • Micro ATX motherboards are the cheapest out of the three. You can easily build a budget build with these motherboards.
  • They can also fit into larger cases.
  • Micro ATX boards have the same RAM capacity as standard ATX motherboards. They have up to 4 DIMM slots.
  • It is also a balance between both standard ATX and Mini ITX. It is compact to a certain extent and maintains decent expandability.
  • However, it has fewer PCI-E slots than the standard ATX motherboards, only supporting up to 4 PCI-E slots.
  • Extreme overclocking may not be possible due to fewer power phases on the motherboard.

Mini ITX Motherboard – Pros & Cons

  • Extremely compact
  • Highly portable
  • Aesthetically pleasing
  • Poor overclocking performance
  • Poor expandability
  • Compatibility Issues, not all GPUs will fit
  • Mini ITX motherboards are extremely compact. If you go far enough, you can make a build that you can hold with one hand.
  • Due to its size, it is extremely portable.
  • They can also be aesthetically pleasing. This may be subjective, but smaller builds are generally better looking.
  • Overclocking will be an issue due to fewer power phases on the motherboard.
  • Minimal expandability, only one PCI-E slot, most likely reserved for a graphics card.
  • Compatibility issues are also a thing with these extremely tiny motherboards. Some graphics cards are incompatible with these motherboards. You may have to search for a “mini” variant of a GPU.

What Motherboard Form Factor Is The Best?

Again, it is subjective, you can build a powerful Mini ITX gaming build, but you will suffer from a lack of expandability.

But for a beginner that wishes to build their first gaming or video editing PC, I’d suggest going for a Standard or Micro ATX motherboards.

Both of those form factors are very beginner-friendly, and it is very unlikely that you will run into compatibility issues when installing hardware.

And since games and video editing tend to be intensive on the hardware, you will be generating a lot of heat. Standard and Micro ATX builds tend to deal with heat better than Mini-ITX builds.