Originally Posted by ericeod
I cant say for certain on this particular generation of cards. But I remember a similar problem with 8800GT and 9800GT cards. They were the same card, with the 9800GT just being a rebrand. All you had to do though was bios flash the 8800GT with a 9800GT bios.
Huh I never knew about this. Well maybe it is possible, although it's a bit early to tell. Maybe wait a while to see if anyone has had any success doing it before buying the 770. Or just pick up a second 680. Performance ought to be all the same no matter which card you match your current 680 with.