I just create a rig with 2 Sapphire Pulse RX 580 8GB
with hynix memory, modified both cards with same mod bios. The hash rate i get is good 29-30 mhs per card. But they are getting too much energy. I don't know exactly how much W are getting from the way but in GPUZ they are getting much power. Dual mining ETH + DCR. The second strange think is that the first card is getting more worm with 81' Celsius. and the second with only 74' Celsius same config. In DCR they are getting 890-900 Mhs.
I try to under-volt with -72 in TriXX but the power stay the same.
Tomorrow i will try to get a power meter to know how much power they are getting from the wall.