Nvidia Geforce Gtx 680 MacFeb 17, 2019 While the 680 and 770 are based on same basic core, by the time the board partners made the 770 they all went in their own direction with components. Most notably the VRAM, fan(s) and power management varied from card to card. In comparison, most 680 cards, expecially the 2GB ones, used similar parts, hence the ability to use the 'Mac rom' on. Apr 19, 2013 ..