Ever notice how every now and then AERO will disable for a little while? Well I have, and tonight I noticed that my GPU fan started spinning up. So I checked task manager for CPU load and came across WINSat. Bit of research turns up that it is the Windows System Assessment Tool and for some idiotic reason Microsoft sets it to run every single week. Who knows why. Anyway, open Task Manager under Administrative Tools and disable WINSat, as I've read some people have this happen in games and other full screen apps.
ASUS Sabertooth 990FX/Gen3 R2, FX-8350 w/ Corsair H60, 8 GiB G.SKILL RipjawsX DDR3-2133, XFX HD 7970 Ghz, 512GB Vertex 4, 256GB Vector, 240GB Agility 3, Creative X-Fi Titanium w/ Creative Gigaworks S750, SeaSonic X750, HP ZR2440w, Win 7 Ultimate x64