Running esxtop from the command line will give you the information - my experience is nominal - but will vary with load and what its doing - if you are using IP Based storage you will see great network usage -
Actually Hypervisor doesn't do anything. the Kernel however is what is running. It depends on the number of VM's also.
Each VM adds about 200-500 Mhz of overhead to the machine, depending on the guest OS.
So technically it could be zero or it could be 2Ghz.. It depends
Thanks. I've heard of 8-12% overhead introduced by the hypervisor in ESX - is that a reasonable number? I know that the memory overhead will cary depending on the number and type of workloads/OSs etc.