Frequently Asked Questions by customers, end-users, and integrators. Let us know if you have an unanswered question.
Make sure the date and time span or Query String is defined to return a subset of data instead of all of the data.
You can also reindex the database in SQL Server to run faster.
Reorganizing and Rebuilding Indexes
http://msdn.microsoft.com/en-us/library/ms189858.aspx