[citation][nom]Filiprino[/nom]You can try to write as many times as you want the word "heavier" and "much", but the reality is that the number of system calls made and the number of context changes does not affect that much, nor the drivers are performance hogs. Windows on the other hand with its Direct3D (Xbox 360 uses a derived API) may well be as Valve showed and now they will try to mitigate Direct3D lower performance.[/citation]
The difference in performance, snappiness, and memory consumption between even small Linux distributions such as TinyCore (runs better with 64MiB of RAM than Windows XP does with 512MiB and otherwise identical hardware, Windows 7 can't match it unless it has at least 2GiB) and Windows XP is huge, let alone compared to much heavier OSes such as Vista, 7, and 8. Using something that is similarly small as well as highly optimized for the hardware is even better.
Graphics drivers on Windows can use far more memory than a console's entire OS needs. The games on Windows that are ported from the consoles use several times more memory than they need on the consoles even when you play on comparable settings and they need much more CPU performance to run those comparable settings, the graphics performance is undoubtedly also poor in comparison to a console that has similar graphics hardware just like everything else is.