512 only make a couple of fps difference at the most as no game takes up the whole of 256mb vram in games yet but i think my pc is the clostest to yours so far
that is if you havnt clocked your conroe
;P
today ive had the chance to try out my x1950pro in a conroe setup of my friends Meny thanks rankle(nick)
e6600 @3.15
1gb of kingston ram
asus p5w Dh
with my x1950pro at stock it wouldnt clock for some reason but here are the screen shots
and 1 taking on his overclocked x1900gt vs my stock x1950pro 635/1480