OpenGL vs. Vulkan Performance For Portal 2 With Radeon Linux Graphics

With Valve's Portal 2 having added a Vulkan renderer by way of DXVK for converting Direct3D calls to Vulkan, here are some initial benchmarks with several different AMD Radeon graphics cards for seeing the performance of this nearly decade old game on Linux with the existing OpenGL rendering path compared to that of the new Vulkan rendering option.