ATI has now released the final revision of its Catalyst 4.9 drivers which should bring some performance improvement, especially in the new generation Radeons. Get them [URL=http://www.ati.com/support/drivers/winxp/radeonwdm-xp.html?type=xp&prodType=graphic&prod=productsXPdriver&submit.x=7&submit.y=9]here[/URL].
Doom3 performance improves 10-15% on ATI RADEON™ X800 XT products when anti-aliasing is enabled. UT2004 performance improves considerably on the ATI RADEON™ 9500 PRO, RADEON™ 9700 PRO RADEON™ 9800 PRO and RADEON™ 9800 XT products. The benefit can be 25% or more in some circumstances, particularly at extreme graphics settings such as 6xAA + 16xAF.