CNET labs has followed up some of their previous Microsoft Windows Vista Service Pack 1 (SP1) testing, including using a laptop (Dell XPS M1530 to be precise).
this round of testing exposed some interesting issues, including one that many laptop users may encounter these days:
The one area where we saw a significant performance degradation with SP1, however, was when writing the folder to a USB 2.0 hard drive. We saw between a 44- and 54-percent degradation on Vista SP1 versus Vista. It’s difficult say exactly what is causing this performance drop.
They also didn’t see any significant change in laptop battery life or application performance.