Client called,   application response dropped from 5 sec. to 2 min.  We profiled traffic,  60% statements  related to historical reports. Likely client has 2 Enterprise edition SQL2005

We set data mirroring between servers and on mirrored server created sql agent job Every 15 minutes drop and recreate database snapshot. Then redirected all historical reports to point on database snapshot.  Current application response time bellow 1 sec.

Current report execution time 10 sec.