Motherboard form factors refer to the layout, features, and size of a motherboard. This includes the kind of power supply that will be needed. As well as the number and type of ports available, the location & number of the mounting holes – which in turn affects the kind of computer tower you’ll need.

Types Of Motherboard Form Factors:

motherboard form factors chart

This motherboard form factors chart was lovingly crafted by /r/pcmasterrace

The two most popular are ATX and Micro-ATX. However, there are well over a dozen other form-factors that have existed and been used over the history of computing.

Some of these include:

  • – EATX
  • – Mini-ATX
  • – Mini-ITX
  • – AT
  • – Baby-AT
  • – LPX
  • – Mini-LPX

What is the most common motherboard form factor?

atx motherboard diagram

The most common type of form factor is ATX (Advanced Technology Extended motherboard). Introduced in the 1990s it has been the dominant form factor ever since.

What is the difference between ATX and EATX?

The difference between the two of these is that EATX is larger. It stands for Extended-ATX and allows more RAM slots among other things. They are growing in popularity with gamers for obvious reasons.

What is the biggest form factor?

Today the biggest form factor on the public market is EATX. However, the WTX (Workstation Technology Extended) was much larger at (356 × 425 mm) vs (305 × 330 mm).

Are smaller motherboards slower?


First of all, these days you’re probably not going to want to use anything smaller than a micro-ATX. With that in mind, you’ll not generally find these boards run slower. They have fewer features and the smaller size makes them more susceptible to suffering from heat-related issues. In my experience, these boards never last as long as a regular ATX does. As for the speed though that depends on the motherboard itself, not the form factor.

Current Form Factors

Today there are only a small number of form factors in use compared to how many have ever actually been manufactured. These are the important ones that you need to know about unless you’re into the history of tech.

1. ATX

ATX was an evolution of the Baby AT form factor but was improved in several key ways. Just as prior to ATX the AT and Baby AT had dominated, the ATX has now dominated since the mid-1990s.

Size: (305 x 244 mm)

2. Micro ATX

The Micro-ATX is a smaller version of the ATX that allows users to build computers that are far more affordable. If you don’t need more than 2 RAM slots or more than a single graphics card, the Micro-ATX has been saving you money for years if you’ve been using this form factor for your builds.

Size: (244 × 244 mm)


The EATX is slowly gaining in popularity and allows users to buy the most expensive boards out there and fit as many components in their computer as is physically possible. This allows people to create the most powerful gaming computers out there. If you’re not using one of these a lot of people would argue that you’re not running a high-end gaming PC.

Size: (305 × 330 mm)

4. Mini ATX

Mini ATX is an even smaller board than the Micro-ATX and they do often get confused, of all the form factors still being used today this is the rarest and probably one that you’re even going to struggle to find online. In general I wouldn’t recommend them except for in the case of enthusiasts.

Size: (150 x 150 mm)

5. Mini ITX

This form factor is growing in popularity recently and it offers a much smaller set of working dimensions than a Micro ATX while not being as small as a Mini ATX. Some enthusiasts as well as certain types of ‘budget gamers’ really love what the mini itx has to offer.

Size: (170 × 170 mm)