So according to this video I watched Windows 8 seems like good OS for performance in that matter. If you can get past Metro or disable it, then it's a great OS.
http://www.youtube.com/watch?feature=player_embedded&v=B6192ie9MbU
Windows 8.1 comes out this fall, and Microsoft's horns are showing: Bing Search will be on by default for all searches (as if search works on Windows8), and there is no way to turn it off: SPYWARE!
Just stay with W7 and block everything and uninstall search and indexing, it is good enough for the few games and Adobe programs that still need Windows, and upgrade your PC to GNU/Linux for everything else!