There are some driver issues with windows 8 from what I've heard, but as long as you have nvidia which is on top of drivers there should be no problem.
AMD works as well... sometimes :P
I had a really strange problem yesterday. I was getting huge fps-drops after playing games for a while. I checked the temperatures, and it turned out the drops started when the GPU temperature reached approx. 68C. I then downloaded the latest AMD driver (some beta version), and now the problems are gone.
Would anyone mind explaining how the hell that worked?