You might check out some video card tweakers. I'm using Riva Tuner, but it's an older version and they may have added some more features in the newer versions.
The one program that might have the tweak your looking for is the GeForce Tweak Utility. Be careful though, as messing with settings you don't know about can mess up the performance. It has a ton of tweaks, and might have what you want. Plus, it's free. :)
I don't have a link ATM, but searching Google should bring it up quickly.