quote: Linux; though, I think it's still OpenGL-based, rather than Direct3D/X.
quote: On the plus side, OpenGL optimizations have been going very well for Valve. In the two years since Steam launched for OS X they got Source to run very fast on it, and they currently have Source games running faster under Linux than they do in Windows. Granted, 315fps in Linux vs 270fps in Windows gives no practical benefits since it is already so fast, but it is still worth noting.
quote: Incorrect, they released all of those details. Hardware was a GTX 680, Intel i7-3930k, and 32GB of RAM, and the operating systems were Windows 7 and Ubuntu 12.04
quote: Source engine games use DX9, not DX10 or 11, so that part is irrelevant.
quote: The version of OpenGL being newer is also beside the point, it took months of optimizations and custom driver work to get L4D2 on Linux to go all the way up from 6fps to what they're running now.