Just like any other PC builder, you've probably considered building an SFF PC at least once. You may not have gone through with it, but the allure of crafting a compact yet powerful machine is intoxicating. That said, not everyone should dive headfirst into SFF (small form factor) PCs without considering the inevitable challenges of a compact build. The project might seem straightforward on the surface, but it can throw curveballs at you if you aren't prepared for what you're getting into.

5 You'll have to make tough component choices

It's all about the art of balancing

If you have built mid-towers and full-towers before, and think that going SFF simply means getting a mini-ITX motherboard, then you're sorely mistaken. The limited space inside an SFF case impacts almost every aspect of the PC. From the size of the graphics card, power supply, and the CPU cooler to the number of fans and NVMe SSDs on the PC, you need to spend a considerable time planning the build before actually getting on with it.

Since you can't just drop in any beefy triple-slot graphics card inside a compact case, you might have to pick a less powerful GPU than you initially intended. It's not just about the physical limitations, but also the thermal constraints of an SFF PC (more on that later). Similarly, you might have to pick an SFF power supply instead of the regular ATX form factor, which usually costs more. Even the CPU cooler needs to be carefully considered since your case might not fit a 360mm AIO or a massive air cooler.

Moreover, your mini-ITX motherboard will inevitably make compromises in one or the other areas, such as the number of M.2 slots, USB ports, PCIe slots, or ARGB headers. Many things you're used to in a mid-tower will cease to exist in an SFF build, so you need to prepare yourself before building an SFF PC.

4 Every millimeter counts

Most builders learn it the hard way

If you've built multiple PCs before, you've probably used cases where space is aplenty, component compatibility isn't a concern, and cables can be stuffed anywhere your heart desires. On an SFF build, however, you need to be extra careful about cable management, component clearances, and even cable thickness. Space is a premium in any SFF case, and after squeezing in the biggest graphics card, cooler, and fans you can, there's very little of it left for anything else.

Even if your GPU's product page confirms that it's compatible with your SFF case, some extra cables on the sides can throw everything out of whack. Your CPU cooler might be too close to the side panel, the supposedly compatible radiator might be too thick, and your fingers might struggle to route cables properly behind the motherboard. Working with an SFF case is significantly harder than anything else, and only when you realize this are you ready to take on your first SFF build.

3 Optimizing airflow and noise levels will be tricky

More than usual

Another aspect that becomes slightly complicated in SFF builds is airflow. Since you have limited space to work with, the scope of routing fresh air into the system is already low. You need to be deliberate with the cooling hardware you choose. The CPU cooler fans and case fans should be of the static pressure variety instead of the airflow ones, so that they can push air through the crowded interiors of the case.

SFF cases are also more susceptible to being noisy since fans have to work overtime to achieve the same level of airflow as seen in regular-sized cases. You could try fitting larger fans that can spin slower while maintaining the same amount of airflow, but that might not be possible in every case. The alternative would be to use fewer fans than you initially decided, so that the overall noise levels remain low. Then, you'll need to use an optimal fan configuration for your particular case to ensure system temps remain within reason.

2 Upgrades will rarely go your way

The sequel of compromises

While your upgrade route is always somewhat limited based on your initial build, this is especially true with SFF PCs. Firstly, the limited space will dictate which components can physically fit inside the case. And with graphics cards getting bigger and bigger every generation (RTX 50 series Founder's Edition cards being a rare exception), you'll probably have to compromise yet again when you go for a GPU upgrade.

Switching from your low-profile air cooler to a fancy AIO might also be hard if your case doesn't have a compatible mount. And even if you manage to get your favorite component to physically fit inside the case, the process of swapping the components will be anything but simple. You'll need to disassemble a lot of components to reach that NVMe drive or those PSU cables. In a nutshell, upgrading components on an SFF build isn't impossible, but it surely isn't seamless.

1 Less freedom to experiment

A different kind of esthetic

Finally, an SFF PC somewhat limits your ability to make your rig look the way you want it to. For instance, the limited number of components inside means you don't get as many chances to add RGB lighting to your build. The reduced fan headers and ARGB headers compound this issue as you're forced to use fan hubs, and not everyone likes to do that. The lack of space might also prevent you from adding GPU sag brackets, thick SSD heatsinks, or cable extensions.

It's also near-impossible to have dual chambers or space for custom watercooling loops inside an SFF case — that's yet another design choice eliminated. It's not like SFF PCs can't look great — there are plenty of them that do — but you're still restricted in terms of making sweeping changes to the build to personalize it the way you want. After building several mid-towers and full-towers, you might not care about that, but you should go in with that understanding.

SFF PCs can be great with the right mindset

An SFF PC shouldn't be the first PC you build; it should fall somewhere down the line on your PC building journey. Once you've experienced everything SFF PCs can't do, you'll be ready to appreciate what's great about them. At some point, you'll crave the challenge, portability, and convenience of a compact PC, and will be ready to build around the challenges that come with it.