Hello Jaideep, I probably can't give you the info you're looking for, but I did have a copy of our PROD instance running on a Windows 2003 VM machine for a while to use to learn the upgrade to 9r. This had WebLogic and the db was on a separate Oracle RAC server. It was slow even after the VM team upgraded the memory and put it to multiple cpu's. It sped up once I followed the Ariba's Performance Tuning Guide - to make sure each node starts up with java parameters suited to the environment. You want to maximize this as much as possible without exceeding your hardware. I don't think I would do a virtual environment for a production instance though.