SpeedFan

SpeedFan is a program that monitors fan speeds, temperatures and voltages in computers with hardware monitoring chips. SpeedFan can even access S.M.A.R.T. info for those hards disks that support this feature and show hard disk temperatures too, if supported. SpeedFan can even change the FSB on some motherboards. At the lowest level, SpeedFan is an hardware monitoring software, but its main feature is that it can control the speed of the fans (depending on your sensor chip) according to the temperatures inside your pc, thus reducing noise and power consumption.