R9 270X in my case. The Rx 3xx and newer (and they're slowly porting it to older devices) use the newer AMDGPU driver stack, which is supposed to be even better

R9 270X in my case. The Rx 3xx and newer (and they're slowly porting it to older devices) use the newer AMDGPU driver stack, which is supposed to be even better, but I haven't tried that myself yet.