I think it should work on that ATI card, aslong it isnt too outdated and has a decent amount of MBs, i know little of ATI cards to be honest but as far as i know the RE4 was originally for gamecube, then ported to ps2, then to PC and gamecube is suposed to use ATI, wich means it might somehow have better support on ATI. hope that helps.
as long can handle p.s. 2.0 it will run fine