Originally Posted by Gorath 
IŽll leave the explanations about graphics driver tweaks with CoolBits to somebody else.
I believe ATI has an option to turn on/off Vsync via the driver but nVidia does not so you need to do the CoolBits registry "hack" to enable more features in your driver.
- Install the latest official nVidia ForceWare driver (91.47 as of today).
- When asked to reboot, click on 'Later'.
- Go to Start -> Run -> regedit
- Look up HKEY_LOCAL_MACHINE\Software\nVidia Corporation\Global\NVTWEAK
- Right click on the entry and create a new DWORD value
- Name it "CoolBits" and enter "3" when prompted for the value (for SLI systems, you need to enter 18 to get the most out of ForceWare)
- Reboot and then check your nVidia control panel for some new options like Vsync on/off and more fan control etc
If you don't like playing with your registry, then just download
CoolBits 2.0 from Guru3D (or any other hardware site, of course).