The release of GNOME Shell and GNOME 3 is fast approaching. Unfortunately for many the latest build is nearly unusable due to the slow animation speed and lack of mouse responsiveness. If you have an NVIDIA graphics card you may be in luck as the fix is fairly simple. You need to change to the latest recommended NVIDIA drivers.
To install the recomended NVIDIA drivers navigate to the Additional Drivers menu.
System -> Administration -> Additional Drivers
You should have 2 proprietary drivers available. Choose the recommended driver which should be your second option.
Now restart your system and launch gnome-shell.
$ ./gnome-shell --replace
Your desktop should now operate more quickly.