AMDGPU-PRO 17.10 vs. Mesa 17.1 RADV/RadeonSI Performance
With Counter-Strike: Global Offensive at 1080p, the results were very close between these two AMD Linux driver options on the Polaris and Fiji graphics cards.
When moving to 4K though, the pure open-source (AMDGPU + RadeonSI) driver stack did manage to deliver a rather nice advantage over the AMDGPU-PRO driver derived from Radeon Software's OpenGL binary driver.
With Deus Ex: Mankind Divided, which is one of the rather demanding Linux OpenGL game ports by Feral Interactive, the performance is much better with RadeonSI than AMDGPU-PRO 17.10.