High CPU usage or irregular behavior occurs in virtual machines that are running in Windows Virtual PC

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Article ID: 981285 - View products that this article applies to.
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SYMPTOMS

When you run a virtual machine in Windows Virtual PC, you may encounter the following behavior on certain hardware platforms, such as notebooks:
  • You experience high CPU usage in the guest operating system. However, when you examine Task Manager, no CPU usage issues are displayed in the host operating system.
  • Keystrokes in the guest operating system are delayed.

CAUSE

This issue occurs because of the advanced power saving features that are built into the hardware of some notebooks.

RESOLUTION

To resolve this issue, use one of the following methods:

Method 1

  1. Shut down all the virtual machines that are running on the computer.
  2. Start Notepad, and then click Open on the File menu.
  3. In the Open dialog box, type %localappdata%\Microsoft\Windows Virtual PC\Options.xml in the File name box, and then click Open.
  4. Replace <mm_timer_duration type="integer">10</mm_timer_duration> with <mm_timer_duration type="integer">1</mm_timer_duration>.
  5. In Notepad, click Save on the File menu, and then close Notepad.
  6. Open the Power Options item in Control Panel, and then make sure that the current power plan is set to Balanced or High Performance.
  7. Start the virtual machine.

Method 2

  1. Shut down all the virtual machines that are running on the computer.
  2. Start Notepad, and then click Open on the File menu.
  3. In the Open dialog box, type %localappdata%\Microsoft\Windows Virtual PC\Options.xml in the File name box, and then click Open.
  4. Under the <virtual_machines> tag, add the following line:
    <enable_idle_thread type="boolean">true</enable_idle_thread>
  5. In Notepad, click Save on the File menu, and then close Notepad.
  6. Open the Power Options item in Control Panel, and then make sure that the current power plan is set to Balanced or High Performance.
  7. Start the virtual machine.

    Note This method enables Windows Virtual PC to fully use the processor and prevent the system from entering a low power state. For multicore systems, one core is used.

Method 3

  1. Disable the Advanced Power Management options in the system’s BIOS.
    Note For more information about how to do this, contact your computer manufacturer.
  2. Open the Power Options item in Control Panel, and then make sure that the current power plan is set to High Performance.

Properties

Article ID: 981285 - Last Review: March 12, 2010 - Revision: 1.0
APPLIES TO
  • Windows 7 Enterprise
  • Windows 7 Home Basic
  • Windows 7 Home Premium
  • Windows 7 Professional
  • Windows 7 Ultimate
Keywords: 
kbexpertisebeginner kbsurveynew kbprb KB981285

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