We have performanceproblem in our SQL server2005. Indexes are rebuilt, statistics are updated and slow queries are tuned however the sql server is still slow! In task manager CPU usage is around 3% sometimes goes up to 50% when we try to run a query through out web application. and the other problem is that PF Usage gets so high. Server has 8GB of RAM and PFUsage sometimes goes to 4GB or 7GB other values in task manager is as follows: totals: handles: 21145 , threads 1164, processes 70 Physical memory: total: 8386216, available 4435588, system cache 1510852 commit change: total: 4171988, limit 10030600, peak 4256540 Kernel Memory: total 131980, paged 87172, nonpages 44820 I wonder what really causes our sql server become slow. It is slow even if no user is connected to our application. Could anyone tell me how I can resolve this problem.