Information about power management setting on a network adapter

Article ID: 2740020 - View products that this article applies to.
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Summary

The enhancements made to Windows 7 for managing power settings for network adapters greatly reduces the number of spurious wakes, allowing computers to sleep for longer periods of time when idle. Furthermore, you can configure the power management settings to meet the needs of your users through device properties, standard registry settings.

When deploying Windows 7 or Windows Server 2008 R2, you may want to disable the Allow the computer to turn off this device to save power network adapter power management setting on some computers.

More information

The Allow the computer to turn off this device to save power setting controls how the network card is handled when the computer enters sleep and can be used if a driver misrepresents how it handles sleep states. Windows never turns off the network card due to inactivity. When this setting is checked(enabled), Windows puts the network card to sleep and when it resumes it puts it back to D0. When this setting is not checked(disabled), Windows completely halts the device and on resume reinitializes it. This setting is useful if a network card driver says it supports going to different sleep states and back to D0 but it ultimately doesn’t support this functionality.

You can use Device Manager to change the power management settings for a network adapter. To disable this setting in Device Manager, expand Network Adapters, right-click the adapter, click Properties, click the Power Management tab, and then clear the Allow the computer to turn off this device to save power check box.

In Windows 7 or Windows Server 2008 R2, you have two additional check boxes on the Power Management tab for the Network Adapter that defines whether this device can wake the computer:

  • Allow this device to wake the computer
  • Only allow a magic packet to wake the computer
Note: For above mentioned settings to work, you may also have to enable BIOS settings to enable WOL. The specific BIOS settings depend on the manufacturer of the computer.

However, with some Windows 7 or Windows Server 2008 R2 installations, you may want to use the registry to disable the Allow the computer to turn off this device to save power network adapter power management setting or to configure the wake options described above.

How to use Registry Editor to disable network adapter power management on a single computer

Important This section, method, or task contains steps that tell you how to modify the registry. However, serious problems might occur if you modify the registry incorrectly. Therefore, make sure that you follow these steps carefully. For added protection, back up the registry before you modify it. Then, you can restore the registry if a problem occurs. For more information about how to back up and restore the registry, click the following article number to view the article in the Microsoft Knowledge Base:
322756 How to back up and restore the registry in Windows

To have us disable or enable the network adapter power management setting for you, go to the "Fix it for me" section. If you prefer to disable or enable the network adapter power management setting yourself, go to the "Let me fix it myself" section.

Fix it for me



To disable or enable the network adapter power management setting automatically, click the Fix it button or link. Then click Run in the File Download dialog box, and follow the steps in the Fix it wizard.



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Disable network adapter power management setting
Microsoft Fix it 55016
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Enable network adapter power management setting
Microsoft Fix it 55017
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Notes
  • You have to select the device that you want to disable or enable in the DeviceNumber list during the installation of this Fix it solution.
  • This wizard may be in English only. However, the automatic fix also works for other language versions of Windows.
  • If you are not on the computer that has the problem, save the Fix it solution to a flash drive or a CD and then run it on the computer that has the problem.

Then, go to the "Did this fix the problem?" section.



Let me fix it myself

To use Registry Editor to disable the Allow the computer to turn off this device to save power network adapter setting for a single computer, follow these steps:
  1. Click Start, click Run, type regedit in the Open box, and then click OK.
  2. Locate and then click the following registry subkey:
    HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class\{4D36E972-E325-11CE-BFC1-08002bE10318}\DeviceNumber
    NoteDeviceNumber is the network adapter number. If a single network adapter is installed on the computer, the DeviceNumber is 0001.
  3. Click PnPCapabilities.
  4. On the Edit menu, click Modify.
  5. In the Value data box, type 24, and then click OK.

    Note By default, a value of 0 indicates that power management of the network adapter is enabled. A value of 24 will prevent Windows 7 from turning off the network adapter or let the network adapter wake the computer from standby.
  6. On the File menu, click Exit.

Did this fix the problem?

  • Check whether the problem is fixed. If the problem is fixed, you are finished with this section. If the problem is not fixed, you can contact support.
  • We would appreciate your feedback. To provide feedback or to report any issues with this solution, please leave a comment on the "Fix it for me" blog or send us an email message.

ADDITIONAL INFORMATION

You have 3 options for the power management properties of the Network Card:
  • Option 1: Allow the computer to turn off this device to save power
  • Option 2: Allow this device to wake the computer
  • Option 3: Only allow a magic packet to wake the computer
The different possible combinations which exist along with their DWORD values (in decimal and hex) are:
  • Option 1 and option 2 are checked, Option 3 is un-checked: This is default and hence its value is 0
  • Option 1, option 2 and option 3 are all checked: The value becomes 0x100 (256)
  • Only option 1 is checked: The value becomes 0x110 (272)
  • Option 1 is un-checked (Note that option 2 and option 3 will be greyed out as a result): The value becomes 0x118 (280)
A conflict happens for the DWORD value for the last step where Option 1 is only checked, if the following steps are done exactly as mentioned below:

  • If you check all the boxes, then the value is 256 (0x100).
  • If you un-check the box 1, which will grey out the other two, the value becomes 280 (0x118).
  • If you check all the boxes except, the 3rd one, PNPCapabilites value becomes 0.
  • If step 2 is repeated, the value becomes 24 (0x18).
Now, the values are different for the same setting because the way it has been achieved.

For deployment purpose, to keep the value for Allow the Computer to turn off this device to save powercleared, one needs to use the value 24 (0x18). Reason being, by default the option 1 and 2 are checked, which is same as DWORD value 0 of this key (even though the key does not exist in the registry by default). Hence, creating this key with a value 24 (0x18) in the deployment script/build process will inject this entry in the registry which in turn should uncheck the first box during server startup.

In the same way, if you want to keep the Allow the Computer to turn off this device to save power checked and the Option 2 and 3 cleared, the required value would be 10 (0x16).

Note: This is entirely by design.

References

For additional information about How to disable power management for a network adapter when you deploy Windows XP, click the following article number to view the article in the Microsoft Knowledge Base:
837058 How to disable power management for a network adapter when you deploy Windows XP
Note This is a "FAST PUBLISH" article created directly from within the Microsoft support organization. The information contained herein is provided as-is in response to emerging issues. As a result of the speed in making it available, the materials may include typographical errors and may be revised at any time without notice. See Terms of Use for other considerations.

Properties

Article ID: 2740020 - Last Review: November 2, 2012 - Revision: 2.0
Applies to
  • Windows 7 Home Premium
  • Windows 7 Enterprise
  • Windows 7 Professional
  • Windows 7 Ultimate
  • Windows 7 Service Pack 1
  • Windows Server 2008 R2 Standard
  • Windows Server 2008 R2 Standard without Hyper-V
  • Windows Server 2008 R2 Enterprise
  • Windows Server 2008 R2 Enterprise without Hyper-V
  • Windows Server 2008 R2 Datacenter
  • Windows Server 2008 R2 Datacenter without Hyper-V
  • Windows Server 2008 R2 Service Pack 1
Keywords: 
kbfixme kbmsifixme KB2740020

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