google "omega Drivers" i found with my old ati9600xt 128meg card that the omega drivers, whilst having some quirks, got me higher frame rates during gaming
If you have a recent card you should be able to find current drivers at ATI's official site (http://www.ati.com/support/driver.html) but if you're using an older card you may have a better chance at one of the sights that the guys above gave.