SpeedFan can access digital sensors available on your pc. By acessing available hardware monitor chips, SpeedFan can show temperatures, voltages and fan speeds. SpeedFan can show S.M.A.R.T. data from almost evey hard disk too. Temperature sensors from almost every manufacturer are automatically detected and accessed. Usually, the only action you need to take is to rename the readings that SpeedFan found. If your hardware allows it and you properly configured SpeedFan, you can change fan speeds depending on system temperatures, thus reducing overall noise.