i have MSI RX 590 ARMOR OC.. first time i tried  PhoenixMiner_5.5c, i had 15 Mh hash.. i tried mod bios. cumpute mod.. amd miner drivers, and nothing appened.. still 15 Mh.. i tried to restore all, and now i have 9 Mh of hash.. there is some tutorial to put it at 30 mH... i google and can't find nothing usefull