I've posted it in here recently, but here it goes:
- Open Regedit
- Travel to HKLM\software\NVIDIA Corporation\Global\NVTweak
- With "NVTweak" still highlighted, right-click in the right window pane
- Select new -> DWORD value
- Name this new word "CoolBits" (it's not case sensitive)
- double-click the new Coolbits DWORD to open the value's properties box
- In the "value data" box, enter "3" and insure that the Hexadecimal selection is checked
- Exit Regedit
Now, when you right click on the desktop, properties -> settings -> advanced, the tab with all the performance settings should have a new option called "clock frequency settings". You can manually adjust from here...
The latest drivers now flash a user agreement at you when you go to manual each time, and you have to scroll through the thing like you're actually reading it before you can check "agree". Other than that, it's a great little utility.