AMD has updated their Catalyst drivers for Linux, with this package being aimed exclusively at owners of their "Professional" series of cards such as their ATI FireGL line. The new 8.49.7 Linux driver adds some considerable performance boosts in CAD applications and OpenGL, with the press release claiming jumps as high as 33% over older drivers.
The driver is compatible with other Radeon cards, though they've made it a point to highlight the FireGL series as receiving the most benefit from the update. You can get the update for yourself from AMD's site or read the press release.