I have a a SQL Server 2012 (SP1) #cu5 (X64) instance used as SharePoint 2010 back end and for the most part use only 10 - 30% CPU but there is a high CPU usage when running FAST search crawl(both incremental and full ).
Following Microsoft recommendation for SharePoint SQL instances Auto Create and Auto Update Statistics are turned off and SharePoint is supposed to take care of statistics and index maintenance using health analyzer rules and timer jobs. For the most part it does ok job but up on investigating the queries creating high CPU usage I found out there are missing statistics but i cant create them since modifying SharePoint databases will make them unsupported.
Please let me know if you have been in a similar situation and any helpful advice will be appriciated. Also let me know if you think http://sharepoint.stackexchange.com/ is the best place to post this instead of DBA SE.
SQL Server Environment: HP ProLiant DL385p Gen8, Microsoft Windows Server 2008 R2 Enterprise SP1, AMD Opteron(tm) Processor 6204(single Socket, 2 Core, HT enabled) Microsoft SQL Server 2012 (SP1) #cu5 (X64)
SharePoint Environment(I don't have much detail on this right now): SP 2010 SP2(2 app server, 2 Web server, 1 FAST search server)