I have gone back to 5.11 drivers because of the system taken up by the new CCC in the ATI drivers from 5.12 onwards, the control panel option has been dropped forcing users into the CCC config. I had evil fps drop across the board and used some tuning tips I garnered from a post in "another" forum, but even using the tips, which are a PITA to setup, the drop was still there just not quite as bad. I have recently bought an AX850XT AGP card to replace my 9600xt, still using the 9600xt atm tho cos the 850 was wrecked during delivery, along with an Audigy 4 and some other stuff, by the courier, so I will check again once it gets returned to see if the newer card suffers as badly.
Sys Spec
AMD 3000+ barton
1.5 gig PC2700
256 Sapphire 9600xt
Creative 5.1 digital
Sam