Capacitor — first thing that affects reliability. Solid caps made in Japan are the best. Second best are solid caps made somewhere else. Third best and lousiest are liquid caps. Liquid caps assure your computer will die in 3–5 yrs max.

PCB — Printed Circuit Board. Generally speaking the more layers the better. More layers mean that signals from one component have a more direct path to another component. It also helps keep RF down by having more grounding layers — FCC class A vs class B. Color doesn’t matter. Copper is standard material for traces.

VRM — Voltage Regulator Modules. These components get very very hot. Noticed? Keep them cool.

VRM Phases — the more phases doesn’t mean it’s better. It means that the mobo chipset can work better with the CPU to go into more intermediate power states and save electricity.

Think of a car with a 4-speed transmission vs a 9-speed transmission. Both cars will stop, start, go, and reach highway speeds. However, the 9-speed transmission car will be more fuel efficient at around-town speeds.

BIOS. It’s important to choose a mobo from a reputable manufacturer that will update the BIOS 2,3, 5 years from now. Strange problems will occur and you need a BIOS update to fix it.

One time we had an Everex mobo w/ 16 MB of RAM. It wouldn’t boot. With 16 or 17 MG of RAM it would, but not 16. Turns out the way the BIOS remaps itself into high RAM caused the problem.

The good thing is that all mobos are tested with Windows for sure. If the system boots to Linux as well, I’m 98% sure that most of the serious BIOS bugs have been removed as well.

MOBO Reputation. Nowadays you have to go by the reputation of the manufacturer. I’d rank the manufacturers like this: Asus, Asrock, EVGA, Gigabyte, MSI, and the others after. Your mileage may vary.

RAM. FYI, some mobos may be picky about the kind of RAM that’s installed. You should check the mobo mfg’s HCL as a reference.