Use the following procedure to specify the CPU requirements of a virtual machine. These settings do not specify actual hardware; however, Virtual Machine Manager (VMM) uses these settings to calculate host ratings and to set CPU resource allocation.

You can use this procedure when creating a hardware profile, modifying a hardware profile, or configuring hardware profile settings from the New Template Wizard or the New Virtual Machine Wizard.

1. In the left pane, under Hardware Profile, click Processor.

2. Modify the CPU options as follows:

   1. Number of CPUs. Select 1, 2, or 4 CPUs from the drop-down list box. The maximum number of CPUs depends on the virtualization software of the host. For more information, see Supported Hardware Capabilities.
      
      
   2. CPU type. Select the CPU type from the drop-down list box.
      
      
   3. Compatibility. To improve compatibility between hosts with different processor versions and virtual machines running older operating systems, you can configure options that limit the processor functionality of a virtual machine. Setting the following options provides you with more options for matching the CPU settings for a virtual machine to actual processor hardware on a host during placement or migration:
      
      
      • New in VMM 2008 R2, you can set the Allow migration to a virtual machine host with a different processor property to allow a virtual machine to run on a host that has a different processor version than the host on which the virtual machine was created. The virtual machine must be stopped to set this property.
        
        

        Important
        Setting the Allow migration to a virtual machine host with a different processor property allows for greater flexibility in live or saved-state migrations; however, it reduces the functionality of the virtual machine’s processor. So you should use this only when necessary, such as to facilitate live migration between clustered hosts that have different processor versions.

      • Some older operating systems running on virtual machines, such as Windows NT, might not be compatible with newer processors on hosts. You can set the Run an older operating system property to make the virtual machine compatible on hosts with newer processors.
        
        

See Also