Civilization VI is one of the latest Linux game releases, just premiering a few days ago. Civilization VI was released for Windows last October while the Linux port by Aspyr Media came just last week. Under Windows this AAA game has a Direct3D 11 renderer and experimental Direct3D 12 renderer but under Linux just has OpenGL support.
With minimum quality settings at 4K, the Direct3D 12 renderer on Windows 10 was faster by a few frames than D3D11. Under Linux, the OpenGL-rendered game was much slower. On Linux this new game with NVIDIA Pascal graphics was just getting 60~70% the performance of the Windows build.
With ultra quality settings, the Linux results remained much lower than Windows. The D3D12 performance here ended up being lower than D3D11, but the Linux performance was at half the speed or worse. Under Linux this game appears to be heavily CPU bound, even with higher-end hardware like the Core i7 7700K used for this benchmarking.