I'm good with my XFX RX 480 8 GB cards. 3 GPU's mining at 80 Mh/s overall with 60 W power draw of each according to GPU-Z (of course I know that it's far from being accurate). Not much of overclocking done because I don't want my any of the GPU's to die or to lower the life duration.
You are doing okay and I think that is pretty nice, you also should not overclock it because it can get you into trouble and its also that its really lowers the life duration significantly.
These cards are by the way pretty powerful so that is nice.