Did you manage to resolve this issue?
We are running an Oracle 10.0.2.3 over NFS with a brand new FAS2220 (only purchase in Nov 2011) with the same Ontap version and having the same issue.
We've migrated the Oracle Data/Log/Redo/Control and temp files to local disk storage. Brought the Database up and ran a simple query which took 6 seconds. After migrating the data/log/redo/control and temp files to the Netapp storage the same query took 42 seconds to run. This simple select statement only fetches 50 records from the database.
We have opened a case with Netapp and ran a load of perfstats that they are currently investigating.
This sounds exactly the same issue that we are experiencing.