So you've just stumbled upon the Small Form Factor PC community, and are interested in getting started. But there's so much information available, and looking at the community spreadsheet can be really daunting. So here is a brief guide and FAQ for newbies who are looking into getting started with SFFPCs.
The most common definition of a SFF PC is a system with a total volume of less than 20 liters. However, for the purposes of this subreddit, any build focused on space efficiency, or packing a lot of power into a small space, is welcome.
This subreddit isn't really the best place to learn the basics if you're brand new to PC building. There are fantastic resources over at /r/buildapc, including their wiki which is a great place to start when it comes to understanding the basics of PC building. Almost all that information applies to SFF PCs, just... smaller. If you have specific questions around parts compatibility for SFF PCs, search the subreddit to see if its been asked and if not, feel free to ask in the sticky thread.
It depends on your parts and their age. Most often, the parts that make it difficult to downsize are your Motherboard and Power Supply (PSU). 99% of SFF cases require the use of a Mini-ITX motherboard (often abbreviated to just ITX), which are very small boards (170mm x 170mm square) usually with a single PCIe slot. If your existing PC uses an ATX form factor motherboard, there's still hope for you but your options are much more limited. Look into the Sliger Cerberus X or the SFFtime P-ATX.
Finding ITX motherboards for older CPUs (especially Intel ones) can be very expensive. You may get lucky on eBay or /r/sffpcswap, or you may find that keeping your i7-6700K or 7700K is more expensive than just buying a new board. If you're on Ryzen, you have the advantage of being able to buy most AM4 boards and just having your chip work, but beware of very old chips on newer boards and vice versa. Always check the CPU compatibility list for the motherboard.
If you have a LFF PC today, you probably also have an ATX Power Supply, which is much larger than the smaller SFX PSUs that are commonly required for SFF PC cases. While there are some cases that support ATX Power Supplies, SFX units provide many more options. Cases that support full-sized ATX PSUs would be the Silverstone SG13 and SG14, or the Cooler Master NR200(P) with the 3d-printed bracket. Some SFF cases also come with power supplies included, like the NZXT H1.
Poorly built or poorly planned SFF PCs will have bad thermals, which is also the case for LFF PCs. If you put a bunch of RGB fans behind a glass panel in a full tower, your thermals will be terrible as well. 😀 Well thought out SFFPCs can have amazing thermal and noise performance, but there are trade-offs between noise, performance, size, and cost.
There's SFF Network and its associated forums, as well as some great YouTube channels focused on SFF PCs like Optimum Tech, Gear Seekers, Hardware Canucks, The Tech Buyer's Guru, and even Linus Tech Tips does cool SFF PC stuff every now and then. The subreddit also has a weekly rotating sticky for Case & Parts Recommendations where you can ask questions. You can also join our Discord!
This depends on your region, as in certain places the various Chinese cases (listed in the community spreadsheet with a Cyan background color) may be easier to come by than others. If you're in North America or Europe, buying these through brokers can be challenging or may be a little scary for some getting started. I'll focus here on the non-TaoBao cases, but that's not to say they may not be the best option for you.
Note that these are my personal recommendations and not an official endorsement by anyone. All of these cases are "mass-market" cases from large manufacturers and so should be easy to find in stock and order.
This isn't a new case, in fact it's pretty old, but it's a great starter case for a few reasons: It's cheap, it's small, and it can fit existing ATX PSUs. You can drop most ITX systems in here without issue, it has great compatibility with modest GPUs, and because its so cheap modding it is pretty low risk. There are years worth of SG13 posts on the subreddit where you can find example builds or questions about the case answered. Some great resources here here and here.
The NR200 may be the most popular new ITX case released in 2020. After several swings and misses at making SFF cases, CoolerMaster really nailed this one, if the multitude of builds posted to the subreddit are any indication. It's true SFF at only 18 liters, has excellent compatibility for up to 3-slot GPUs (although 70mm/3.5 slot thick cards have been found to fit), has great compatibility for both air and water cooling, offers a tempered glass side-panel option, and is under $100 MSRP. What's not to love? There's an outstanding post by /u/belak51 covering air cooling in this case, along with some links there. If you're going to use a closed-loop liquid cooler, don't mount it in the bottom.
The Original Gangster of SFF Cases, the NCase M1 was the trailblazer and in many ways fostered the SFF community we have today. Even though it was first released back in 2013, it is still relevant today and strikes an incredible balance of size, function, and aesthetics. While this technically isn't a "mass-market" case, availability has been pretty good as of late, and its pedigree deserves a mention here. The NR200 above owes much of its design and layout to the M1 - think of the NR200 as an M1 but 40% bigger. Reviews of the M1 are pretty dated because the case has been around so long, but here's a more recent one. Also, for the ultimate air-cooling build guide, see /u/M1AF's incredible build guide here.
Historically, one of the biggest criticisms by folks trying to get into SFF PCs is that the best cases are always either out of stock, on back order, or no longer even in production. These are often made in batches, and you may need to pre-order a case and wait weeks or months before you can get one. To add to that, they are often much more expensive. That's not to say they aren't worth it, however! The founding fathers of the SFF scene were all boutique cases, like the original Greatest-of-all-Time NCase M1, the original Sandwich Design Dan A4-SFX, and the console-style pioneer Skyreach 4 Mini. Nowadays you can find dozens of boutique makers on this subreddit or on SFF Network making incredible cases, and you have manufacturers like Sliger with a full line of SFF cases with different layouts.
If you want to get started with one of those cases, you are more than welcome to, but I wanted to keep this beginner's guide focused on easily available options. Personally, I've been waiting more than a year for my next case, because as you find out once you go down the rabbit hole of SFF, you start to get a little crazy. 😁
In conclusion, if you do decide to embrace the madness with all of us here, we want to welcome you and ask that you make sure you read our community rules before posting. Check the rotating sticky thread if you have simple questions, refer to the community spreadsheet, and please use the search function to see if your question has been asked! You can also join our Discord if you'd like to chat more real time.