Look here:
https://bugs.launchpad.net/ubuntu/+source/compiz/+bug/768275/comments/5
I found that disabling fglrx and using the open source drivers improves a lot the speed for my card:
01:05.0 VGA compatible controller: ATI Technologies Inc RS880 [Radeon HD 4200]
Of course also proprietary drivers should work, but the above is a good solution
Look here:
https:/ /bugs.launchpad .net/ubuntu/ +source/ compiz/ +bug/768275/ comments/ 5
I found that disabling fglrx and using the open source drivers improves a lot the speed for my card:
01:05.0 VGA compatible controller: ATI Technologies Inc RS880 [Radeon HD 4200]
Of course also proprietary drivers should work, but the above is a good solution