Hi, I want to build my first mining rig but my head is completely spinning with all of the options or should I say lack of options. GPUs seem to be very difficult to find nowadays and the ones that I can find are limited in quantity at most places to one or two per purchase. So I'm just curious what GPUs have you guys used most recently and why? Where'd you get them from?

Would it really make a difference if I had several different GPUs from different manufacturers in the same mining rig? Also, I saw one video on YouTube where a guy said that most people only build 6 or 8 GPU mining rigs because anything more than that just becomes a pain in the ass with bios updates and crashes. Is it really that much more difficult to have a 12 GPU or 19 GPU mining rig?