I had the same problem with one of my 6 cards setup on windows 10, (worked fine for ETH mining) tried everything , uninstall amd driver , used DDU , tried 1 card connected to the mobo , installed different drivers (older newer) nothing helped .. Finally after a long hours to try to find out what the hell going on , i decided to reinstall win 10 and the latest amd driver . That is fixed my problem , after that the 6card setup hashing perfect with genoil's miners