I had a similar problem with a query that was being run in a ms access front end vs. me trying it directly on sql server. Access was taking 30 seconds, sql server was taking <1 second.

Turned out when the access called sql was being run, sql server wasnt using an index, which it was when run directly in query analyser (I did some background checking and looking at query plans to find this out).

I added a index hint to the access sql on a field/index in question to force its use, and BANG, <1 second in my access version.

martin