Just a heads up, ATI just released cat 8.6 so might see some improvements to 48x0 performance

Vista x64
http://ati.amd.com/support/common-vista64.html

Vista x32
http://ati.amd.com/support/common-vista32.html

XP
http://ati.amd.com/support/radeonx-xp.html

Looks like some improvements to 3dMark Vantage, CoD4 and QuadFire improvements/support