We just migrated several old Windows 2000 SP3 servers to vSphere environment, those servers have our J.D. Edward Xe B7333 SP21 client on it. After we migrated, we found out the performance is too bad. A report can be generated by old server in about 4 minutes, but the migrated took about 8 minutes to do so. We even tried to let 1 ESX server to only host this migrated machine. It is still slow. This happened to all migrated machine.
We also have another vm on Xen Free 5.5. Installed with same JDE client. It runs faster.