Hi!

There are many factors that can affect performance of the VM. Basically, the VM is like a black box -- you cannot really measure performance and compare it to real hardware, as resources are dynamically allocated as needed, and I/O is likely the weakest point of the VM.

What is the physical number of CPUs in the virtual domain? How much physical RAM is allocated to VM guest? What is the version of ESX vCenter?

First, I would suggest to configure the number of guest OS VPUs (cores) to be identical to the number of physical CPUs (cores) in the ESX configuration. Then I would allocate a decent amount of RAM to the VM.

Make sure to use fairly new kernel (2.6.38+) for the guest OS.

Also make sure that you use appropriate drivers for the hard disk controller and network card eg PVSCSI and VMNET3 in the guest kernel configuration.

See if any of the tweaks above bring any benefits and post your results!

Andrejs