At first I thought it was the cpu fan but I put a new fan in yesterday and the noise was still there so I put my ear up close to theback of the power supply and it seems that it is the power supply making the noise. I just built this comp 2 days and and every since my first boot up it is a permanent winding noise like a baseball card on a bicycle tire. It's not extremely loud but it's to the point where it's annoying. I installed win7 last night and everything is running fine and core temps don't go above 42c while playing WoW and CS:S at the same time.