ok ive gone back to stock rom.
used some ver 20 drivers as the latest causes the clkernal prob.
set watman to cvoltage 900mv as lower seems to result in crashing.
left memory alone but changed to memory timing 2.
getting 29.8 mhs and so far stable with about 104W power draw.
Still alot, and you said this gpu has samsung memory ? I'm confused mate, your voltage should drive down under 800mv, I can do this successful on my rx580 with samsung memory, I suggest you get samsung BIOs and mod the gpu then or download smOS and flash BIOS in the OS