A question by Loki got me looking at the state of DirectX/Direct3D and OpenGL. We hear Windows runs games faster on Direct3D than on OpenGL. That is supposedly why Second Life™ viewers run slower, fewer Frames Per Second (FPS), than other games using Direct3D. But, some people say otherwise. One of those people is Steam or more accurately the online gaming company Valve.
Valve makes the Source Engine that runs Half Life 2, Left 4 Dead, and Dota 2. Valve is not a Microsoft fan, which I don’t find surprising as Microsoft is known for trying to make Windows a closed shop that keeps other gaming systems at a disadvantage. In testing in August 2012 Valve reported that OpenGL on Ubuntu ran faster than DirectX/Direct3D did on Windows. You can read more about that in: OpenGL is Faster.
This tells us it is not just OpenGL and Direct3D that solely control performance. The OS has quite a bit to do with it also.


