best gaming OS

There is nothing wrong in what I said, Shanti  
You've just figured it whole wrong way ...

I didn't mean games compltely independent from the OS.
Game quality obviously depends on OS's ability to manage HW resources. However no software would help your hardware weakness, because the most important thing for quality gaming is kick ass HW (and DSL connection).
99% of modern OS's programmed to make the good (sure not the best) use of hardware resources, some handle memory alocation better then others, some support more CPU's or RAM ...
but in generaly OS is only the tool to communicate between game (or any oher application) and hardware.

p.s. I'm never taking guesses since never affraid to say I don't know sth and nobody knows everything, you know ...

Cheerz
Thanks for taking care of quality of our rapping