I just installed 17.10 on my machine with a X4 950 (A320 chipset) and RX 560. According to the "additional drivers" tab none are in use and the only available option pertains to AMD CPUs, not GPUs. How do I get best performance?
As shown by numerous recent benchmarks on Phoronix, the open-source RadeonSI driver that comes preinstalled will serve you best for OpenGL workloads (i.e. most games and software like Blender and Krita). If you require Vulkan (a new API used by certain recent Linux games) support, you can install the
mesa-vulkan-drivers package. The only currently lacking feature in the open-source drivers compared to Catalyst/AMDGPU-PRO is OpenCL compute API support and HDMI/DisplayPort audio, both of which should be available within a year.