A couple of days ago I had to convert an old windows 2000 server to VMWare using Vmware converter (P2V).
After the conversion, It seemed like the windows 2000 virtual machine consumed a high CPU usage from the ESXi host.
In the vSphere vCenter the virtual CPU indicate 100% CPU usage.
Inside the VM, the Task manager showed a normal cpu usage.
After a little investigation it appears that Windows 2000 only support One virtual processor.
The physical machine was Hyper Thread Cpu, so when I converted this machine, it kept the 2 virtual processors in the guest configuration.
The solution was to configure the virtual machine with only one virtual processor and update the ACPI driver to uniprocessor.
To do this I needed to go to Device manager expend Computer and select the ACPI Multiprocessor PC and select the driver tab.
Click on update driver and than select the Display a list of known drivers click next and select ACPI Uniprocessor PC click next and answer YES on the question popup.
after the installation is fineshed, I rebooted the virtual machine and the CPU usage has reported correctly in the vCenter .