What hashrate are you getting with sgminer?
I have about 30 kH on each MSI Gaming X 8G RX480 (Win7 X64, 16.9.1 drivers, ETH-way modded BIOS, 1303/2200).
Sorry, no AMD, only nVIdia GTX 1070 : 1800 KHs each (x60 RX480), for 70 w max :-).
how many zcoins can you dig every 24hours? and how much kwh does your computer consume?