Dual mining on a mixed RX 570/580 4GB rig I get ~116 MH/s ETH and ~2400 MH/s DCR @ 735W at the wall with a -96 mV undervolt in Afterburner.
ETH - Total Speed: 115.951 Mh/s, Total Shares: 3828(965+968+1015+970), Rejected: 2, Time: 38:23
ETH: GPU0 28.742 Mh/s, GPU1 29.081 Mh/s, GPU2 29.092 Mh/s, GPU3 29.035 Mh/s
DCR - Total Speed: 2434.967 Mh/s, Total Shares: 15575(3877+3869+3930+3907), Rejected: 154
DCR: GPU0 603.589 Mh/s, GPU1 610.709 Mh/s, GPU2 610.935 Mh/s, GPU3 609.734 Mh/s