On vista, you use overdrive to unlock the fan speed. enable it in the CCC then save a profile.
Once done goto
C:\Users\[Insert Username Here]\AppData\Local\ATI\ACE\Profiles
The folder "AppData" is hidden so you can just manually enter it into the address bar in explorer
Open your profile and change the algorithm to Manual and set your speed under "want".http://forums.guru3d.com/showpost.php?p=2751569&postcount=8