The one that i have has Hynix (Sapphire Pulse RX 580 8GB), but i get 30,2Mhash while GPU-Z shows power usage of 93W (i am trying to lower the Voltage at the time).
But i am Using Custom Timings, i found them in this forum, at page 9 or 10 i think, with these timings i could get 30,5 Mhash but i think this costs too much power with higher core clock speeds, so i lowered them a bit and i am Happy with 30,2Mhash.

Works at my Sapphire RX580 Pulse 8Gb just fine, getting 30.2 Mhash at eth Only mining. Thank you very much for posting the Timings
Setting is at Core 1170 Mhz and Memory at 2150 Mhz, Core Voltage @0,9375V, reporting 95W in Gpu-Z.

Somebody asked if the 580 is running fine with 480/470, yes my Setup with 1x580 and 3x 470s is running just fine (All Bios Modded)