OpenGL renderer string: AMD VEGAM (DRM 3.27.0, 4.20.3-arch1-1-ARCH, LLVM 7.0.0)
Dell XPS 9575


AMD's discrete GPU on the Kaby Lake architecture performs significantly worse
under Linux than under Windows. Below are some rudimentary data I've collected:

Game                    Linux           Windows
TF2                     30-50 FPS       60-100 FPS
Borderlands 2           30-43 FPS       42-52 FPS
Minecraft               60+ FPS         40-50 FPS
CSGO                    40-55 FPS       60+ FPS

Notably, Minecraft is the exception, performing much better under Linux for
some reason. 

All of the Source engine games (CSGO, TF2) I tested also had a very severe
stutter, which would happen every other second.