Mini-ITX vs. ATX
One of the attractions of PCs is that they come in all shapes and sizes, and you can build whatever system you want. Some love a full ATX system, while others only ever consider a compact Mini-ITX build. While there have been plenty of form factors over the years, there are four common ones these days: ATX, Mini-ITX, microATX, and Extended ATX (something of a niche). Of these, the battle generally comes down to a choice between ATX and Mini-ITX, but what are their benefits? Which should you use for your next build? Allow us to help.
ROUND 1
Performance
The general perception for a long time was that if you wanted serious performance, you needed a full-sized motherboard and a sizeable full-tower case to put it in. Because, you know, size matters. An obvious win for the bigger formats, then? Not quite. The thing is, the world has changed, and as more and more silicon is squeezed into the CPU packaging itself, you’re losing out less when it comes to dropping down from an ATX to a Mini-ITX or microATX form factor. In fact, when it comes to the core functionality, about the only thing you can lose is support for SLI, because Mini-ITX only boasts a single PCIe slot.
That consideration aside, most MiniITX motherboards boast feature sets that are comparable to their ATX siblings, and when it comes to raw performance, there’s pretty much nothing you can do in a larger case that you can’t do in a well-designed compact chassis. Planning on water-cooling your CPU? Plenty of the cases we look at in these pages support 240mm radiators, and we always consider them in that light, so you’ll be able to overclock your CPUs just as much as you can in a larger case.
Tie: Mini-ITX, ATX, microATX, Extended ATX
ROUND 2
Expansion
What do you really need in your PC? Once you’ve got your CPU, motherboard, memory, graphics card, PSU, and storage in place; what other components do you actually need to make it do what you want? The days of needing soundcards, network interface cards, SCSI boards, and various other goodies are long behind us (thankfully). And while there may be specific instances when you need to reach for such hardware, your motherboard does it all.
The reason we’re talking about expansion is because it’s the main differentiator between the form factors. ATX can, in theory, squeeze up to seven expansion slots into its 12 x 9.6-inch space (realistically, E-ATX is a better option if you need all seven), while the 6.7 x 6.7-inch Mini-ITX boasts a single slot; microATX offers a maximum of four, with SLI/CrossFire a possibility.
Storage is another consideration: Mini-ITX boards tend to have fewer SATA ports, often as few as four, while ATX can easily hit 10. Obviously, smaller cases don’t have room for so many drives, either. So, ultimately, we have to give this one to the bigger form factor, although whether you actually need so much room is another matter. Winner:
ATX
ROUND 3
Compactness
Your choice of motherboard doesn’t necessarily have to dictate your chassis. If you want to slot a microATX motherboard into a full ATX case, you can. It’s the same story for MiniITX mobos as well, because the four mounting screws are compatible with all modern cases (older cases may not be compatible, though, so that’s worth bearing in mind). Obviously, you can’t ease an ATX motherboard into a case designed for Mini-ITX, unless it happens to be a Tardis, but generally you have plenty of options for how you marry up case and motherboard.
The point is: You can still build a huge-ass system even if you decide to go down the Mini-ITX route, but with the advantage that you can actually build a much smaller machine, should that be a requirement. And space can often be a defining factor for new builds, particularly if you want the final machine to sit on the top of your desk, rather than be hidden underneath it. A compact build, with a dash of water cooling, can make for a beautiful thing—an important factor for more and more of us nowadays. Which means that if space is a factor, then it’s hard to go too wrong with Mini-ITX.
Winner: Mini-ITX
ROUND 4
Ease of Build
While we’re big fans of compact MiniITX builds, there’s no getting away from the fact that they don’t always play nice. Confined spaces can lead to scrapes and cuts, but it’s actually the frustration that comes from working in such a tight space that really grinds our gears. You can do it, and the resultant machines can make the effort pay off, but be prepared to spend much, much longer getting everything just right than with an ATX system. A tip on this front would be to connect and build as much as possible outside of the case before sliding your motherboard into place.
Conversely, building inside a large chassis is a pretty straightforward endeavor, with plenty of room for routing cables, space to easily reach components, and sufficient airflow without having to make sure every cable is tied down. You’ll find you have more options when it comes to placing your components as well, whereas in a smaller chassis you tend to find that there’s only one place that your hard drive can go, or your all-in-one radiator can be placed. Adding more components to a bigger chassis is also much easier. So, it’s a relatively easy win for the bigger form factor in this round. Winner:
ATX
ROUND 5
Availability
Not only do you have the most options when looking at ATX motherboards, but new platforms are developed with ATX in mind. It’s where most of the market is, so it makes sense to ensure that’s working first. Other options, such as microATX and Mini-ITX, come later. That’s been fine for years, as motherboard manufacturers have had plenty of lead time to get these niche platforms sorted, meaning there hasn’t been much delay in getting your hands on a tiny motherboard. However, since Ryzen launched, there have been scant Mini-ITX motherboards for us to get hold of, and the options for the new X299 platform aren’t much better— we’re aware of a single X299 Mini-ITX board, the X299E-ITX/AC, which has to work some pretty impressive technical wonders in order to squeeze such a massive socket on to such a small board (like using SO-DIMMs).
The same is true for cases—smaller form factor chassis occupy a niche in the market. Which all adds up to a reduced selection for anything smaller than an ATX motherboard in a tower case. It’s generally worth shopping around to get the platform and form factor you want, but your options will be more limited. Winner:
ATX