Just installed 12.04... This is the first time I run Ubuntu with the Unity UI, not a pleasant experience. The responsiveness is extremely slow (10s after a mouseclick), the screen flickers, etc, all right after logging in. Switching the display driver from Nvidia current to post-release doesn't help at all. What now? Can't go back, but Ubuntu is useless to me right now. What can I do? (The system is a Intel 4x2.4Ghz with 4Gb RAM and a Nvidia 8800.)