http://www.neowin.net/news/main/08/0...service-pack-1
Files copied faster in our initial tests, but other performance was slightly
slower with the SP1 installed.
Microsoft's newly released Service Pack 1 may solve some of the performance
glitches that have annoyed Windows Vista users and discouraged others from
adopting the OS, but it doesn't appear from our initial tests to be a
panacea.
In our first tests of the service pack, file copying, one of the main
performance-related complaints from Vista users, was significantly faster.
But other tests showed little improvement and in two tests, our experience
was actually a little better without the service pack installed than with
it.
Service Pack 1 was released to manufacturing yesterday, and officially sent
out to reviewers today (Service Pack 1 was also unofficially unleashed today
on BitTorrent, too). Service Pack 1 will be available to users in March, as
a download; Microsoft plans to have SP1 integrated into Windows Vista at
retail as well, but could not give a timeline on how quickly the update will
be included in the retail version of Vista.