Just one thing...
Got hands on Sapphire RX470 4GB Mining edition (Elpida). In SMOS I get error, GPU error detected. On windows they are working max 25h/s on 1850mhz (1500strap) without errors.
I think, SMOS has some problems with new mining edition cards because error appears without overclock.
I have the same issue with the mining edition Sapphire (no dvi port and has quad bios). I had to move these GPU's to a windows 10 machine.