Coincidently timed with the release of NVIDIAs latest GeForce 178.24 driver to support their newly released GeForce 9300 and 9400 series motherboards, ATI have too released a new driver set today; the Catalyst 8.10.
The biggest and most notable feature of the latest drivers is the inclusion of manual fan control for Radeon HD 4000 series owners, giving the user more flexibility during overclocking. Another new feature comes in the form of forced Component video detection to better assist those wanting to configure their component video display device settings via the control center prior to physically connecting it.
There's nothing mentioned in the way of performance improvements in the release notes, but sometimes increases can still be seen so it's worth a shot.
You can download the 8.10 Catalyst drivers for both 32 and 64-bit versions of XP and Vista over at the AMD Game! website.