Valve's Linux team has been tinkering around with OpenGL while bringing Left 4 Dead 2 to the format, and has managed to get it running faster than the Windows 7 version. More tech-speak below.
Valve has managed to get the Linux build of Left 4 Dead 2 running at 315 FPS, while the Windows 7 version hit a peak of 270 FPS.
Until however, Valve took its work on the Linux build and applied it to the Windows 7 version, which now hits 303.4 FPS, which is still rather sweet.
The post explains, "Why does an OpenGL version of our game run faster than Direct3D on Windows 7? It appears that it’s not related to multitasking overhead."
"We have been doing some fairly close analysis and it comes down to a few additional microseconds overhead per batch in Direct3D which does not affect OpenGL on Windows. Now that we know the hardware is capable of more performance, we will go back and figure out how to mitigate this effect under Direct3D."