anybody with hasrates for 470 and / or 570 4GB?
ASUS RX570 Expedition OC (modded Elpida bios) clocked at 1225/1940 yields just under 1kh/s. cn_config 7+7. 8+7 seems to be slower.
You've got to give it a go and see for yourself which config will work best, but the above is a pretty safe bet.