I notice this because I have the Arctic Cooling Pro 7 and the fan speeds up when it goes over 30% load or so. I came home before, thought, that's funny, why is the CPU doing something, it should be idling. I had everything closed down and just on the desktop. I haven't seen it do this before. However, when on Windows Live messenger, sometimes it randomly goes up and when you exit MSN it is fine. Any ideas what could be causing this? Sorry for being so vague.