I have a vb.net based website using sql 2008. I run a particular query it runs in few seconds, later I run same query it takes 1-2 minutes or more. 2nd time around there are no others on the system or any other differences than first time around. I noticed SQL takes memory and sits on it. every so often I will see the numbers go down. I am looking at the sql process committed memory column (see attachment). Is it possible to release this memory back after running queries. If not released will it affect performance. I have currently 12gb memory on the server, will having additional 32 or 64gb help? Database is about 150GB , data is loaded weekly or monthly and is only accessed for reporting not for updating by users. for such a database size is there any rule how much memory I should have? I also have additional large databases on the server, including on same drive.