PC case sizes explained: all form factors available in 2025

We’ve outlined the major differences in PC cases and their sizes, but now it’s time to go over the varying use cases between them. Small Form Factor (SFF) builds have risen to prominence in recent years due to their compact design and emphasis on only the essentials when it comes to what they can do. These machines can typically either thrive under a television as part of a home entertainment system, Xbox Series X / PS5 replacement, or as a low-profile workstation, in the same vein as Apple’s Mac mini.

However, the versatile use cases here already have a discrepancy in PC case sizes and their corresponding components. Depending on how small the chassis is, you may need a Mini-ITX motherboard instead of a MicroATX version, which can be far more expensive (and limiting) with its 6.7-inch board versus the 9.6-inch of the latter. That’s ultimately going to be one of the biggest considerations when building an SFF machine, as the super sleek console (and cube) chassis on the market will need specific hardware.

Another associated cost is components such as specifically designed power supplies, but also CPU coolers and case fans made with smaller PC cases in mind. After all, some of the best PSUs will not fit into an SFF chassis, owing to them being (primarily) made with Mid Towers and Full Towers in mind first and foremost.

This includes the premium on power bricks, as seen with the likes of the Cooler Master V750 SFX ($170) compared to the traditionally sized Cooler Master MWE Gold 750 V3 ($99.99) or the Cooler Master XG750 Plus Platinum ARGB ($99.99) from the same manufacturer. That’s a markup of 70%, which is roughly in line with the price increase you can expect from a MicroATX motherboard to a Mini-ITX one (depending on the manufacturer).

There’s no shortage of low-profile CPU coolers for SFF machines, but they’re not going to be the powerhouses needed for leading processors. Popular examples include the Noctua NH-L9i, Thermalright AXP90 X53, and the Be Quiet Pure Rock LP; they’re inaffordable and will suffice for workstation and light gaming use, but will not be appropriate for midrange or higher-end processors. SFF water coolers exist (in single and dual fan configurations) like the Corsair H55 RGB, Be Quiet Loop 2, and the Fractal Lumen S24 v2, but you’ll want to choose a lower TDP CPU and a case with airflow to spare for anything too extensive.

Your choice of graphics card will also need to be considered with an SFF gaming PC. While it’s true that the RTX 5090 and RTX 5080 Founders Edition models can fit into a mini-ITX chassis (being two-slot), the same cannot be said for many of Nvidia’s partners, with some alternatives being triple-slot and even quad-slot, depending on the cooler. This will also be dependent on the size of the small form factor chassis as well, as there’s no set size for anything smaller than a quantifiable mini tower.

It’s not only the width of the GPUs but also the lengths to keep in mind. Yes, there’s the need for clearance on the motherboard, so it doesn’t block anything else, but also the simple act of getting it in the case in the first place. Some Mid-Towers can even struggle with certain models, depending on where the coolers are installed. We recommend checking the dimensions of the GPUs and physically measuring your PC case’s space before you buy anything to avoid disappointment.

SFF machines also need more maintenance than their Mid Tower and Full Tower equivilents, owing to the limited airflow. As a result, they can become dustier faster, which can impede performance over time. Many SFF PC cases feature dedicated mesh panels which can be removed to be de-dusted, but you may need to keep a can of compressed air nearby. Similarly, as many of these chassis do not feature view windows, it can be troublesome to know bad things may have built up until the system starts showing signs of slowdown.