I know this is old but did you ever benchmark some good oc numbers for your RX580? I tried several different adjustments with mine and couldnt get it any better than the stock oc. From what I read, you actually under clock the memory but nothin worked for me. Depending on which 580 u have, there is a bios oc switch somewhere on the board. gives it a nice little boost literally with the flick of a switch.