Valve's experiments with Linux seem to have been very successful so far. The Valve Linux Blog is reporting through optimising Left 4 Dead to work better the the Linux kernel and OpenGL and through optimising the graphics drivers with the help of the manufactures the team has gotten the Linux port of Left 4 Dead 2, which was originally running at 6 frames per second (FPS) on their benchmark machine, up to a colossal 315 FPS. This is compared to the 270.6 FPS of the original Windows 7 version.
This work may not just be of benefit to players of Valve games though, because Valve is helping nVIDIA optimise its drivers this should help all Linux gamers and game developers to increase performance of their hardware. What may be most impressive of all though is that the Windows version of Left 4 Dead 2 is now running faster on OpenGL than it is on Direct3D; 303.4 FPS versus 270.6 FPS respectively.
These results should be definitely be a hopeful light for Linux gamers and should also be of benefit to Source games on the Mac and PS3, which also use OpenGL. Of course this also means Windows users may have the option of rendering through Direct3D or OpenGL in the future, assuming that Valve don't drop Direct3D entirely over this! Be sure to read the full blog post.