was thinking "lolwut?"
the cards a 1024mb card NightCrab

but good point, my friends got the 512 version of the 5770 and im getting the 1gb version.

performance wise, difference?
on his pc, metro 2033 on like, maxxed out graphics lags just slightly when he goes outside and does shit.
will the 1gb version lag like that?

It shouldn't. His GPU lags because there is a large ammount of textures that need to be rendered, this using up all his memory.

At low res, you won't feel that much of a difference. But at high resolutions it will matter.