I'm looking for someone to clarify an outstanding question we've had here at my company. The debate is if you get better performance out of a virtual machine with 1 or multiple virtual processors. It's my understanding that when you give a VM a virtual processor it only gets 1 core of a physical processor in the ESX to use. So one would only assume if you give the VM multiple processors you would make more processing power available to the VM. I know back in the esx 2.5 days they said multi processor VM's could perform slower than single processor vm's. Is that still the case?

We are deploying some domain controllers on virtual machines and I would expect that we would see better performance out of multi processor virtual machines to host the DC's but I've heard that you see a decrease in VM performance when you give it multiple virtual processors.

Can anyone provide an answer on this and any backup documentation that might be useful that I can pass around to my co workers.

hanks

Glenn