Vista uses lots of resources and gaming suffers so if u wanna game on vista specially for those with AMD Processor just download this utility and run it in expert mode before launching the game
AMD Fusion for Gaming
Code:
http://game.amd.com/us-en/drivers_fusion.aspx?p=1
what it does is that it disable all unneccessary services processes anti-virus vista aero theme activates Hard Drive Acceleration activates AMD Boost and other lots of things
