From Alfredo Milani-Comparetti
If you need a tool that 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, then you came to the right place. SpeedFan is the software to go. It is fully configurable and you can create custom events to handle every situation in an automated way. SpeedFan works under Windows 9x, ME, NT, 2000, 2003, XP and Vista. SpeedFan works fine on Vista 64 bit too. The relevant driver is now signed with my digital certificate. And this all costs you absolutely nothing!
What is SpeedFan
SpeedFan allows you to have a deeper view of the status of your computer. Almost every computer includes support for hardware monitoring. Accessing digital temperature sensors is really useful. If you are trying to figure out why your pc hangs when under heavy load or after some hours of usage, SpeedFan might help you to find the real cause. Very often it is a poor power supply, or an improperly installed heatsink that lead to behaviours that we tend to associate with errors from the operating system, but that are not. SpeedFan automatically searches your computer for interesting chips: the hardware monitor chips. SpeedFan can expose voltages,