some of those comparisons are unfair
vista has a completely different architecture than xp
it's a wonder they would even test programs that are designed for a completely different file and system structure...
and the only games that really take a hit are the open gl games which do not have full support yet
I suppose it was a business move for microsoft to make dx10 take priority in their os, as they are still a leading game platform, it seems to me they want to phase out open gl, but that won't be happening any time soon, as all games are designed with open gl software and ported from the design application into the appropriate run time environment
I suppose we can thank the open gl team for this:
perhaps they should install those then try a few open gl games again, that might be fair...