What's New (PowerPivot for SharePoint)
SQL Server 2008 R2 Service Pack 1 (SP1) adds a new configuration setting that lets you control how much disk space is used for caching PowerPivot data on the file system. For more information, see Configure Disk Space Usage (PowerPivot for SharePoint).
SP1 includes a fix for a known installation error that occurs when installing PowerPivot for SharePoint on a server that had prior installation of Analysis Services. You must build a slipstream version of SQL Server Setup 2008 R2 SP1 in order for this fix to be included in the Setup program. Otherwise, you can follow the workarounds provided in the installation instructions. For more information, see Install PowerPivot for SharePoint on an Existing SharePoint Server.
For more information on how to upgrade to SP1, see Upgrade (PowerPivot for SharePoint).