I am using Ubuntu 16.04, driver using AMDGPU-pro v 16.40, it seems the speed is not so high, around 460 h/s. I don't know where to download fgrlx 15.30.3.
I'm with ya man, I have windows 7 right now and it upgraded to driver 16.60 for me, now it's super slow, around 330 h/s. I can't find the old drivers, I'm wondering where the repositories are...