We heard a lot of different performance claims about Vista SP1 in past few months, and now that it's finally (sort of) here, it's time to bust out the stopwatches and see what's what. According to CNET, early tests of SP1 indicate that while there are some performance enhancements to be had, they're mostly driver related -- so if you've been updating all along, you won't see much of an improvement. What's worse, certain tasks like copying files to USB 2.0 hard drives have gotten around 50 percent slower, a speed hit that overshadows the other filesystem improvements in SP1. All in all, though, it looks like SP1 is a worthwhile update -- just don't expect anything to get noticeably faster.