Really the MA770 DS3 supports the 9850 with the F5 bios, they just list it as unsupported because if you overclock it, heat problem with the mosfets overheating starts. But the same problem happens with the 790X, I think they just list it supported just to save face on the 790X and are willing to deal with the problems. If you put mosfets heatsinks on either board you would probable be fine.