The current release cycle for SQL 2005 SP2, is to release a new update every 2-3 months. Currently (November 19th 2007), the latest update for SQL 2005 SP2, is update 4, which is available here : http://support.microsoft.com/default.aspx?scid=kb;EN-US;941450 The updates for SQL 2005 SP2 are all accumulative, so you will not have to install Updates 1 - 3. Each SQL update may contain small changes to the way that SQL Server behaves, including changes to the query optimizer. So when having any kind...