Microsoft invited 15000 testers to download a new version of the Windows Vista Service Pack 1 called Refresh which replaces the version of the Service Pack that was made publicly available. The new build number is 17128 and the usual process of uninstalling the old service pack before you install the new version of the service pack applies.
No news yet on what has been changed in this new release. A tester mentioned a few observations in the Neowin
forum. The new Windows Vista SP1 seemed faster, detected 4GB of Ram correctly but used still only 3.32 GB, noticeably faster explorer tasks and no chattering hard drive after install.
Another user reported that the downloads are available on the official Windows download website. I have not tested these yet and the KB article referred to points to one from last year. If you still want to give it a try you can download the 32-bit
version of the latest Windows Vista Service Pack 1.
Microsoft releasing Windows Vista SP1 Refresh - www.Tech-Dump.com