Dario IT Solutions Blog

Apparently Windows 2000 will provide poor performance after P2V to Hyper-V machine

The reason for that is the Windows 2000 HAL will provide poor performance when you configure more then one virtual processor.

In case you get poor performance from windows 2000/XP Virtual guest machine please do the following:

First of all make sure that you configure the machine to have one virtual processor

Second check what is the HAL of the virtual machine

You can do this by clicking Start, right-clicking My Computer and clicking Manage. Then locate to Device Manager, in the right hand pane, expand the Computer branch and see what it shows underneath the Computer node.

If it is Multiprocessor, you may need to change the computer type to Uniprocessor.
Note that you may need to back up the system so that you can restore it if it cannot boot after changing the HAL (the snapshots of virtual machine may be of help).

1. Click Device Manager.
2. Expand the Computer icon.
3. Right click on the value listed under Computer (either ACPI multiprocessor or MPS multiprocessor) and select Properties.
4. Click the Driver tab and then Update Driver.
5. Follow the wizard by selecting Next and then under "What do you want the Wizard to do?", choose "Display a list of known drivers for this device" and then NEXT.
6. Here is the important step:  if you currently have an ACPI Multiprocessor PC, choose ACPI Uniprocessor PC. If you have MPS Multiprocessor PC, choose MPS Uniprocessor PC. This is critical, make certain you choose correctly.
7. After selecting the correct HAL, follow the rest of the wizard to install the driver. When prompted to reboot, shut the machine completely down.
8. Reboot the computer. Go into Device Manager and see if the correct HAL is loaded.

thanks to this blog.