https://www.stonearch.net/2013/05/13/you-can-upgrade-an-nvidia-gtx680-to-a-gtx770-with-a-simple-bios-flash/
Get a Nvidia GTX770 free! Bios flash and GTX680 not included but required. - Semiaccurate
May 14, 2013 - When SemiAccurate said that Nvidia's GK114 was canceled and replaced with a re-fused GK104/GTX680 we were a bit off, it is exactly the same chip.
free biosgetnvidiaflashincluded