Sort of a DOS but bumped up for the new machinery (64-bit, 1+ TB drives, etc).
This is something I have wanted to do for years! Surely someone has already produced a minimalist dos type OS specifically to run win based games at maximum performance? Maybe there are too many problems with the complexity of windows apps to make it more trouble than it's worth?
This is one of my goals "when I get to be a real programmer"
Try "lack of access to the underpinnings of Windows". Look at WINE... Just hit 1.0, and it's been around for what? 12? 13 years? Same thing with ReactOS.... Complete binary and driver compatibility with Windows... But they have no idea how Windows interfaces with its' various subsystems, and of course, Microsoft isn't going to tell them. They can make educated guesses (quite good ones, in fact), and they'll eventually do it. But it's a slow process.
If you want a fast, Windows compatible OS built just for games... Call Microsoft. See if you can't get them to make an OS that's essentially the Xbox GUI on a PC. Install it, make sure your drivers install, install your games, and that's all that's there. Include a web browser to look up patches. And maybe some other stuff (AIM/MSN/Xfire clients come to mind...). No Office. No Visual Studio. Just the Windows kernel, DirectX, and a really simple GUI that can do all of... Nothing. Build it right, and you wouldn't need a virus scanner either. Or anti-spyware. Or really... Anything.