I am thinking of upgrading my graphics hard to an asus AMD 7770 2Gb, my current card is a sapphire 7700 1Gb. Both are GDDr5. How much of a performance boost would I get?
There isn't a HD 7700. Did you mean HD 7750 ? If yes, than it's not worth an upgrade. Maybe 5 FPS more ? A good upgrade would be the GTX 660 or HD 7870.