If you haven't caught the power company worker outside using your electric meter for a fan, you might wanna head on over to Virtual-Underground and check out their review of the CoolMAX 550W Aluminum with Trilight LED fan.

"Now that you know that there are three fans in this thing you are probably thinking: "Man! That must be loud!" So that is why we have a little switch located on the back of the PSU (rear of the case) with three settings, auto, middle, and low. On auto the fans will adjust to whatever speed they need for better cooling, this is the more quiet setting you can select, then there is the low, fans run at higher RPM than auto, still not  loud at all, then there is the third setting: middle, fans run at their highest speed, moving a lot of air, still very low noise levels."