I'm wondering if it's possible to add different brands of memory in. If a computer has two memory slots and able to expand to 16gb's, can I put 2 different brands of 8gb memory in, or does it have to be paired?
Mixing brands is absolutely fine as long as you don't mind your memory running at the speed of the slowest stick. Also, don't expect it to overclock in the slightest. You'll hit a wall MUCH faster than you would with a matched kit.
I have done several builds now with miss-matched memory and I have never once had a problem. Unless you are running a server of some kind, there is no risk at all. Having more RAM is worth it every time.