I recently discovered that by setting the "Maximum pre-rendered frames", in the Nvidia Control Panel, to zero (0) it is possible to improve the display performance in Windows 7.
After lowering this value which is by default set to 3, you should see smoother animations in Windows 7 and get an overall more responsive desktop environment.
I have an Nvidia GeForce 8800 GT card and by doing this I've improved the responsiveness of Windows 7.
Nvidia explains that the "Maximum pre-rendered frames" only works with DirectX games, however it does have an effect on the Desktop Window Manager (DWM) too.
if only i could have a better cpu, only have an amd athlon 3200+ oc'd to 3.6 ghz n 2gb of ram, the vid card had a gb of gddr3 but thats still nothing at todays standards