Right thought i'd post my tips to get the most out of your radeon so here go's..
I use a tweak program to alter some of the catalyst driver's hidden settings.
I use rage3dtweak to do this
http://www.rage3d.com/index.php?node=r3dtweak
And then change these settings in rage3dtweak as follows.
DIRECT3D
Colorfill - enabled (Improve the colour saturation in games)
Enable wbuffer - enabled (Helps improve speed in Gothic2 on my pc)
Guard band clipping - enabled
W fog - enabled
Z compression - High (Setting this high improves perfomance but might cause artifacting)
Z fog - enabled
Z mask - enabled (Improves 3d speed)
OPENGL
3Dnow! - enabled (Only for AMD cpu's)
Force 16bit textures - disabled (Obviously you want 32bit colour not 16)
SSE - enabled (Optimizations for P3 or above \ AMD xp or above)
SSE2 - enabled (Optimizations for P4 or AMD64)