Here is a useful DMV query for looking at memory pressure on SQL Server 2005.
— Detect external and internal memory pressure
WHERE rounds_count > 0
AND removed_all_rounds_count > 0
The clock_hand column tells you whether the clock algorithm is responding to internal (other SQL Server caches) or external memory pressure. If the values for the rounds_count and removed_all_rounds_count columns are increasing, this is a good sign of memory pressure.
Technorati Tag: SQL Server