We have more or less the same setup with slower queries than old system.

HP BL685c Blades

4 Quad-Core AMD opteron Processors 2.8Ghz

32 GB Ram

HP EVO 6400 San with 8 Enclosures 60 X 146 GB x 15k hdd 3 filegroups

24 GB mem given to sql.

max dop 8

main prod db 10 gb

Windows 2008 R2, SQL 2008 sp1

fail over clustering

db is restored from sql 2005.

app servers and db servers are in the same blade enclosure.

using remoteapp on 4 appservers all connecting to same db.

I dont know where to look anymore.