I have just installed ubuntu 12.04 and then replaced unity with xfce the way described here. Now the graphic performance are poor. The main two symptompts I see are
1. The graphics of some program such as emacs update slowly (I need to alt-tab to refresh the display) 2. Pymol complaints there is not enough memory. Another program I use to view memory has slow response.
Note that I used pymol previously on this machine and it functioned properly. I suspect this is an issue with the intel driver, but I don't know how to test this. The machine I use have an intel i3 processor. I think it's type is 310 or 330. From what I gather, this is also the display adapter.
How can I improve the performance?