You all should probably read through a few of the other threads on this forum.

To get better performance, you should:

-Use Stream SDK 2.1.
-Use the display drivers from Catalyst 10-11.
-Turn off crossfire if possible.
-Use Linux. I've heard that people had problems running DiabloMiner in Ubuntu, so I might suggest Debian instead. There are guides for getting many miners up and running on different linux platforms if you're unfamiliar with how to use it. Look around on the forums to find them. Get ready to use the command line.