I have this crazy problem. I moved a database from one SQL server 2000 to another. The old one is a much slower server with a single processor. The second one is new fast and has 8 Processors. Generally the server perform better. Specially with my websites. However, one query in particular which is the most complex one is very slow.... 10 to 16 times slower. I can't figure why. I rebuild the indexs and both servers are running server 2003 enterprise edition. Rebuilding indexes improved the performance overall, but not that query. Slow server gets back results between 1-4 seconds... the fast new server gets back results in about 16-16.785 seconds. Any clue why? Apperantly my servers settings must be different or memory cash id different but I can't tell exactly the problem. Small queries with large results are much faster.... but complex queries with similar results are slow!!