Yes i suppose backup287, But lets be fair how much difference does the extra memory make between the 640 and 768 on the GTX, all of 1Fps. Memory is a bit misleading after 256mb theres really not much need in games, ok so 512mb is a SMALL improvment over 256mb for games.
... I run FarCry Max Settings, 4x AA (max allowed) 16x Filtering and average about 70 - 90Fps, 60-70Fps in demanding situations.