Huge Difference in FPS from OSX and windows 8

I have a 2011 27" iMac with 6770m, 4gigs of ram, i5 (stock lower end 27")and windows 8 installed through bootcamp. I wanted to use it for gaming only to think that it was unusable. Recently I had realized that all I had to do was to lower the resolution. I was able to play BF3 at 30 FPS on medium settings and Arma 2 DayZ mod at around 40 FPS both at 1600 x 900. The next day I turn my computer back on after shuting it down from the last day, and the FPS on both games had dropped with the same settings down to ~10 FPS. I tested out Minecraft and tried to get the max fps possible (small windowed mode, disable vsync, max fps, tiny rendering) and got around 180 FPS, I went over to OSX and got around 500 FPS with the same settings. I unistalled and reinstalled my drivers, restarted smc, neither worked. Any help would be apreciated