Nvidia nTune for nForce Chipsets...

NVIDIA® nTune is the ultimate utility for accessing, monitoring, and adjusting your system components, including temperature and voltages with clear, user-friendly control panels. Overclock your system for highest performance or underclock it for near silent operation. All changes are performed within the Microsoft® Windows® interface – enabling full functionality without the need to make changes in the BIOS and reboot your system.
This is the main welcome screen...

This is the "Manage my System" interface.....

If you have an nForce 680i System you can change all these settings....

If you want to uTune to automatically optimise your system this is what happens...