For those who like minute control of their system, CPUCooL is a set of very tiny system utilities that you can use to tweak the settings of your CPU and motherboard.
CPUCooL monitors the temperature, fan speed and voltages for many motherboards (check supporting files for supported systems). It includes a utility for shutting down the PC with a single key combination, and a basic optimizer for Cyrix, AMD and Intel chipsets.
A newly included option allows for varying the CPU frequency via the SMBus. If any of this makes sense to you, you might want to check it out. If however, it does not, you will probably want to stay away.