(This is a continuation of http://dba.stackexchange.com/q/20416/3928)

A fellow database developer believes we are having memory issues.  He has seen increased run times in some standard queries - going from under 10 seconds to about two and a half minutes.  He looked at Task Manager on the server and found high memory usage and now wants to take some of the memory currently allocated to the OS and free it up for SQL Server.

We are on SQL Server 2008, a 64-bit machine, AWE is not enabled, minimum 4096 MB, max 10240 MB.

I found Brent Ozar's [A Sysadmin’s Guide to Microsoft SQL Server Memory][1] which indicates Task Manager is not reliable.  I have also found that our Page Life Expectancy is not indicating memory pressure. (Checked via [Pinal Dave's query][2].)

Where else should I look?  What else should I check?  I'd like to report back to the database developer to either confirm his suspicions or prove them incorrect.


  [1]: http://www.brentozar.com/archive/2011/09/sysadmins-guide-microsoft-sql-server-memory/
  [2]: http://blog.sqlauthority.com/2010/12/13/sql-server-what-is-page-life-expectancy-ple-counter/