All new Gigabyte GV-R797OC-3GD with f80 bios are like that.
I tried  to reflash it with f72 bios, but it didn't work.
And I still didn't find suitable bios for them.
I have about 680 kh/s with them at 965Mhz/1500Mhz tc 10240 with latest beta AMD drivers.