This is more a driver issue I think. I like Netrunner a lot and it is a Manjaro spin. When I played GoI last I got 25 FPS! .o. I'm not quite sure what to make of it either! I am using Catalyst on my system as it is supported on netrunner and I would like to keep in archland if I can. Is there something I can do to aid this?
I am aware AMDGPU-PRO has gotten better and better though I would rather not do science and just wait for full support for my 370. These FPS issues have seeped over to CS:GO as well as I have gone under 80 FPS where I was at 150 and up before.