SpeedFan Controls Fan Speed via Motherboard!

SpeedFan is a freeware program that monitors fan speeds and temperatures in computers with known monitoring chips. Its main feature is that it can control the speed of the fans according to the temperatures inside your PC, thus reducing noise and power consumption. SpeedFan can also access S.M.A.R.T. HD data and temperatures (if available). I've downloaded a copy & am trying it out now. Very cool!