Do you have UEFI enabled in the BIOS? Check if you can reset the BIOS to verify if the problem persist.
I saw this on the Gigabyte BIOS version U1L(UEFI BIOS)

1. Beta BIOS
2. UEFI BIOS
   (When updating from legacy to UEFI, use only the utility attached to your BIOS file) 

(Note) Some GIGABYTE utilities are not supported under UEFI BIOS architecture. Please remove Smart6, Dynamic Energy Saver, Smart TPM, and Touch BIOS utilities before updating the BIOS.
Did you update your mainboard to the latest version and installed it following this instructions?
The 6850 is not UEFI ready but the 290 it is.
Is it possible you can test the 290 in a different system to verify results?