As they both (3000 and 4500) have the same default clock, they are equally fast - except 4500 is slower on 2D as the driver doesn't support hardware acceleration on 4500, at least not on all functions where 3000 is supported. It's principally written for 3000 and just happens to work with 4500 - probably after some tweaking. On very big game screens (principally unplayable) 4500 may give ½-1 fps more.