After days of debug i found the solution with this motherboard.
Drop Windows 10 with this board and install Windows 7. All your GPU will be recognised in no time.
Forget about windows 10. Not to mention i have better performance with windows 7.
A noticable hash rate difference in all your GPUs? What percentage increase did you see with w7?
Maybe the issue was with my system but with 6GPU i was running neoscrypt at around 7200 on windows 10 and 7800 on windows 7