SLES-9 EBS 11i 10g 64-bit RAC is not load balancing the DB Tiers

We have a strange situation where after conversion to 64-bit 10.1.0.5 RAC on 11.5.10.2 E-Business Suite, one of our database tiers has about 10 to 20 times the load of the other.  What is even stranger is the over loaded server is not the same from day to day.  Whenever there is any load, one machine ends up with a load average of 20 while the other node has a load average of about 1 or 2.  The DB Tier machines are 4 socket dual core HP DL 580s with 16 GB of RAM.

When we were on 32-bit RAC on 32-bit hardware, same release of the database, the load was evenly balanced.  Apart from 64-bit conversion, we made no changes to the applications side, just replaced the 32-bit machines with 64-bit machines of the same names and installed the 64-bit Oracle CRS and Database Oracle Homes (and followed the Split Tier Configuration Docs from Metalink for our release of the database).

Using Oracle Applications with a Split Configuration Database Tier on Oracle 10g Release 1
http://metalink.oracle.com/metalink/plsql/ml2_documents.showDocument?p_database_id=NOT&p_id=356839.1

Has anyone seen this behavior, or have some ideas of where to start looking for clues why the load balancing is so uneven?

Thanks in advance.


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