Some users with ATI graphics and proprietary drivers are facing a choppy Unity experience. The solution is simple. Install 'CompizConfig Settings Manager' from Terminal or Software Center:
Once installed, press the Window Logo button <Super> and type 'Compiz'. Launch the settings manager and navigate to 'OpenGL' plugin. Disable the 'Sync to VBlank' option and re-login.
sudo apt-get install compizconfig-settings-manager
Once installed, press the Window Logo button <Super> and type 'Compiz'. Launch the settings manager and navigate to 'OpenGL' plugin. Disable the 'Sync to VBlank' option and re-login.