Take a gander at this: http://reviews.cnet.com/8301-31012_7-10319612-10355804.html

The main thing I take out of this article is that OS X DOES things faster where Windows RUNS things faster. The benchmark showing the 3D rendering is a great example. Windows 7 kicked ass. Because the computers were set up with the same basic specs it would seem to me that the processing power is better focused and streamlined with Windows 7. This of course comes with a slight drawback at you see that the batters life for Windows 7 is about 1/3 shorter than OS X.

I also thought this disclaimer was interesting: “Note that this article touched the two operating systems only from the performance point of view. (Mac is also really pretty and Windows offers a lot more options and compatibility.)”