Apparently mosx has never done a Vista/Mac OS X speed test.
Actually, I have.
Its not that difficult to compare OS speeds when the hardware can run both OSes.
But the real difference comes when comparing Windows on good hardware (not a MacBook) to the MacBook itself. When you have a PC that has dedicated graphics and such, the difference between the two OSes becomes even more drastic. For example, DVD playback on a Windows machine with a dedicated GPU can literaly use 20x LESS CPU cycles than on the MacBook with OS X that does NOT take advantage of any hardware features.