At GDC NVIDIA, AMD, and Intel showed that with OpenGL it's possible to driver overhead by 10 times or more. Along with it they can get anywhere from 1.2/1.3x the performance all way up to a staggering 15x if proper time is taking to tune the performance. http://blogs.nvidia.com/blog/2014/03/20/opengl-gdc2014/ It's an absolutely fantastic read, and with the many of the large AAA graphics engines moving towards OpenGL support the future looks bright. Even if we entirely ignore gaming in general, imagine the profound impact this can have on professional work. Everything from CAD, Animation and more. Anything that uses OpenGL. Here's also the video from the Valve Dev Days.