Glenn Berry (@GlennAlanBerry) of SQLskills.com gives some pretty strong arguments for keeping your SQL Server instances current on both Service Packs and Cumulative Updates.
In an effort to encourage you to keep your SQL Server 2012 instances up to date, I wanted to highlight a slew of performance-related fixes that are mostly available only through Service Pack 1 or various Cumulative Update packages.
Recently, Microsoft pushed out Service Pack 1 for SQL Server 2012, and they quickly followed up with Cumulative Update 1 for Service Pack 1. The reason for this is that the service pack – due to longer development and regression testing cycles – did not contain any of the fixes from RTM Cumulative Updates 3 & 4. Since many people have waited – based on mostly speculative bias at this point – to even start testing SQL Server 2012 until Service Pack 1 was released, I thought it might be useful to cover a couple of the scenarios you might come across.