SpeedFan is a freeware program that monitors voltages, fan speeds and temperatures in computers with hardware monitor chips. With SpeedFan you can change your computer's fan speeds, read the temperatures of your motherboard and your hard disk, read voltages and fan speeds and check the status of your hard disk using S.M.A.R.T. or SCSI attributes. With SpeedFan you can change fan speeds according to the temperatures inside your pc. This reduces noise and power consumption. SpeedFan can even change the FSB on some hardware also.
You can configure Temparatures, Fans, Speeds, Voltages etc by clicking Configure button in the above figure. For help file on how to configure above things, just start SpeedFan program then press F1. Now in the help file you will find how to configure information and other related useful information.
Please note that SpeedFan is an extremely powerful tool. Changing the FSB is an advanced option. So try it only if you know what you are doing.
SpeedFan supports Win9x, WinME, WinNT, Win2k, WinXP and Vista.