Cumulative Update 1 contains hotfixes for the Microsoft SQL Server 2008 issues that have been fixed since the release of SQL Server 2008.
Note This build of the cumulative update package is also known as build 10.00.1763.00.
We recommend that you test hotfixes before you deploy them in a production environment. Because the builds are cumulative, each new fix release contains all the hotfixes and all the security fixes that were included with the previous SQL Server 2008 fix release. We recommend that you consider applying the most recent fix release that contains this hotfix.
For more information visit: http://support.microsoft.com/kb/956717/en-us