Head out to buy a new case and the first thing you’ll notice is that all of your options share a specific pattern. Each case should mention if it’s E-ATX, ATX, M-ATX, or Mini ITX compatible. 

Sometimes, you may even come across dual-system or SSI EEB cases. But, what’s the point of all that? 

Why is it that size is so important? Are there any advantages or disadvantages to each type of case? Anything that we should keep in mind? This article has been made to answer all these questions and more. So, here’s everything that you need to know about PC case sizes!

Mini-ITX/SFF

If we exclude Nano-ITX, which is practically useless for 99.9% of the population, Mini-ITX is the smallest form factor that you can get.

They are often cheaper than their bigger siblings. But, the only way to achieve that small form factor and cheaper price tag is by sacrificing features, room for components, and thermals. 

To be more specific, most SFF cases will offer enough room for a couple of drives, a single small to medium-sized GPU, limited water cooling support or none at all, and in most cases, no pun intended – very limited room for CPU coolers. 

Unlike mid or full towers (More about those in a minute), Mini-ITX cases do not come on a standard shape or size for that matter. They are all designed to fit Mini-ITX motherboards, but the designs that they use to achieve that differ quite a lot. 

For example, it’s not uncommon to see cube-shaped SFF cases that can fit all the PC components in one section in order to save up precious room. 

Pros: 

  • Very small
  • Generally cheaper

Cons: 

  • Bad thermals
  • Limited room for components, liquid cooling, and fans
  • Cable management is a challenge

M-ATX

Micro ATX cases are made to fit M-ATX motherboards while in some cases, they can also get up to ATX. 

Since they are bigger than Mini-ITX options, they can generally fit larger components, offer more support for liquid cooling, while also offering better overall thermals. 

You’re generally looking for enough room to fit in 4 drives, 240mm radiators, 4 to 5 fans, and bigger CPU coolers, GPUs, etc. That being said, most options still don’t offer support for bulky 165mm coolers. So, do keep that in mind. 

M-ATX cases are also known for offering the best balance between size and performance. They are just large enough to fit in a PC that your average user is likely to buy. 

More size also means more room for fans and air to push into the case. So, this also makes M-ATX options much better for cooling. 

Pros: 

  • Enough room to fit in medium-sized components
  • Acceptable cooling
  • Most options can fit in 240mm radiators
  • Usually enough room for at least 4 drives

Cons: 

  • Despite their larger size, most cases are still unable to fit in bulky coolers
  • Cable management is often a bit challenging

ATX – Mid-Tower

ATX is more or less the average/ideal size for your average PC builder. Mid-towers will usually have plenty of room to fit not only ATX motherboards, but also M-ATX and Mini-ITX ones as well. 

Thanks to their slightly larger size, they offer better cooling, more room for components, better cable management, and sometimes, a bit of modularity as well. 

Most of the time, there is enough room for at least 4-5 fans, 5 drives, 280mm radiators at the front or top, dual-GPUs, 160mm coolers, and some of the biggest GPUs that one can find. Overall, they are the go-to choice for workstations, gaming PCs, and also for low-end computers that can later be upgraded to something more powerful. 

Some Mid-towers may also offer support for E-ATX motherboards, 5.25 bays, multiple drive slots, or even 360mm radiators. But, that being said, most of them stay out of the enthusiast territory. 

Overall, if you’re someone who’s looking for a medium-sized case with decent cooling and plenty of room for components without spending too much, an ATX case is probably your best bet. 

Pros: 

  • Good cooling
  • Plenty of room for components
  • Can fit multiple drives and fans
  • Good cable management
  • Pricing is just about right

Cons: 

  • Most options are still unable to fit in 165mm coolers
  • Leaves a lot to be desired for enthusiasts

E-ATX – Full Towers, Ultra Towers, Dual System

Full towers are slightly larger than standard Mid-towers. In exchange for their bigger size, they offer plenty of room for everything that you may need and great cooling. 

The vast majority of them can fit in the bulkiest coolers, biggest graphics cards, at least 360mm radiators, more than 6-7 drives, and more than 6 fans. Not to mention that many of them offer a bit of modularity as well. 

There are many options that also offer 5.25 bays which you can use for optical drives or case accessories. And while optical drives are almost extinct, that doesn’t mean that you can’t use the 5.25 bay for a fan or HDD controller

Ultra towers are even bigger than full towers and are most suitable for enthusiasts who want a lot of modularity, lots of cooling, plenty of room for custom water loops, and the best that one can get. 

Dual system cases are usually the largest and are designed to fit at least one ATX motherboard along with a Mini-ITX one at the same time. This allows you to have two computers in one case, which is great for streamers or other professionals who need two different computers/operating systems. 

That’s not to say that the average consumer can’t benefit from a dual system case since they do also offer superb cable management, plenty of modularity, and plenty of room for everything. 

Pros: 

  • Great cooling
  • Support for everything that you may need
  • Superb cable management
  • Great modularity
  • Lots of options

Cons: 

  • Very large
  • Expensive

Wrapping Up

That’s all about or PC case size guide. If you still struggle to understand the differences, here’s the short version: 

  1. Mini-ITX: These cases often have the worst cooling and offer very little room for components, but they are also the most compact
  2. M-ATX: Much larger than Mini-ITX, a bit smaller than ATX. Decent cooling and enough room for your average builder
  3. ATX: Average sized and can usually host both Mini-ITX and M-ATX motherboards. Good cooling and plenty of room for your average builder
  4. Full tower: A bit larger than ATX. Offers more room for cooling, extra drives, and sometimes a bit of modularity
  5. Ultra towers and dual system cases: Mainly targeted towards enthusiasts. They offer a lot of modularity while they can hold the largest radiators and more fans + drives than you’ll ever need