Thanks for your response! appreciate it !

Yes I use SOLARWIND to monitor SQL Performance and It shows that Workfiles Created/Sec and Worktables created /sec are in CRITICAL status.

There is some information from SOLARWIND aboout workfiles :

"Work files could be used to store temporary results for hash joins and hash aggregates. The returned value should be less than 20. Tempdb work files are used in processing hash operations when the amount of data being processed is too large to fit into the available memory."

Possible problems: High values can indicate thrash in the tempdb file as well as poorly coded queries.

and This is some information from SOLARWIND aboout worktables (at the moment, the value is : 739/sec)

"Work tables could be used to store temporary results for query spool, lob variables, XML variables, and cursors. The returned value should be less than 20. Worktables are used for queries that use various spools (table spool, index spool, and so on."

Possible problems: High values could cause general slowdown.

I wonder what should I do ?