FACTORING IN FORM FACTORS
THE VAST MAJORITY OF EX-OFFICE PCS COME IN SFF — SMALL FORM FACTOR — CASES.
They didn’t need to be gigantic for the job they were designed for, but it does mean you’re going to have to think about what you’ll be able to achieve. The case design is often fantastic for quick maintenance; generally hard drive and optical drive caddies are screw-free, the case itself opens in seconds, the RAM slots are easily accessible, and there’s no excess wiring to worry about. But you’re stuck with half-height cards, and it’s imperative that you check the position of the PCIe slot before buying the PC or a graphics card. All too often, it’s located in such a position that only single-slot-width cards work, and so close to the PSU or the side of the case that adequate airflow is impossible.
You may also see USFF PCs, even smaller than SFF. These aren’t much good for us, as they don’t have any space or slots for expansion. There’s a way to add external graphics to them, sure: If you find the right cables, it’s possible to string a wire from a mobo-mounted mini-PCIe socket to an external PCIe card slot. But don’t buy a PC expecting to do this. It’s impractical, awkward and silly. Keep an eye on eBay listings — if one is dealing with multiple lots and says you may receive an SFF or USFF edition of a PC, walk away. Look for a tower case. The extra space makes them worlds easier to work with.