I have just added a "new" DB to my Server (2005), I have restored from a dead SQL2000 server to my active one (2005), and changed the compatibility to 90 (SQL Server 2005). My average CPU was on 48% connections on 1600, after restoring the DB from my side and changing the connection string so that the site will work with the active server hell has broken loose, my connections have stayed on the avg. 1600 but my CPU spiked to an avg. of 70%. I thought ok, I have some tuning problems, so I have rebuilt all the indexes, and started a profiler on the "new" DB, but alas I was wrong on an avg. hour had 100 SP runs and all of them with less than 50 ms CPU and the highest number of reads were 2.2k (no writes and duration less the a sec for most, highest duration 3 sec).
I would love to get directions on what should I check next, SQL Server side or Web side.