There are (I think) 4 Sapphire 7950's. What are the differences between all of these model numbers?
21196-00-20G
11196-16-20G
11196-09-40G
11196-10-40G
Is it just the fans or are there other things to consider? Which do people usually use for mining?
I recommend both the 11196-16-20G and the 21196-00-20G in my
build guides, based on their price points and my personal experience. Both cards are very stable and can be undervolted/overclocked. The main difference between them is one uses a twin fan cooling system (slightly better IMHO) and the other uses a single fan reference design that sucks air in the side of the card and pushes it out the back. With either card, I recommend using supplemental cooling (like a box fan) to keep them from overheating while mining.