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Use PowerCfg in Windows 7 to Evaluate Power Efficiency

It’s quite annoying when you have work to do on your laptop and the battery is dead or low on power. Even if you’ve selected the Power Saver plan, there could be other factors causing the battery to drain too quickly. Today we take a look at using the PowerCfg command to generate a power efficiency report.

Generate Report

To generate the report you’ll need to use the Elevated Command Prompt as Administrator. Click on Start and type CMD into the search box, then right-click the command prompt icon and select Run as Administrator.

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Next type in the following command to generate the report on energy efficiency:

powercfg -energy

It takes a full 60 seconds for the report to generate. and you’ll see the following message in the command screen when it’s finished. Notice it shows the number of errors and warnings contained in the report.

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The Power Efficiency Diagnostics Report is saved in HTML format in your local user drive. Now you can read through the analysis and try to determine what is causing so much power to drain. In this example in the errors section it’s showing Sleep Mode is disabled and a USB device is not turning off when not in use. 

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Sections of Report

So what does this report even mean? Well, it’s broken down into 4 sections and we’ll take a look at each one. The first section of the report contains the basic system information like the system name, BIOS, manufacturer…etc.

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The second section contains the Errors with a red background. These are problems that have a huge effect on power consumption and battery life. Problems classified as Errors can affect battery life by 15% or more. 

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The next section are Warnings that have a yellow background. The problems indicate a moderate effect of power consumption and battery life. They are not as critical to fix as Errors, but if you can fix them, it will help improve efficiency.

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The last part of the report contains informational data with a white background, and don’t indicate any energy problems. This lists the system components that were inspected for the report.

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Conclusion

There is a lot of detailed information is the report and it may not be the most exciting thing to read, but make sure to look over it closely. In the example above we just needed to go into Power Options and configured Sleep Mode and kept the USB Flash drive unplugged when not using it. Each computer will vary and a solution might be tweaking Power Options or installing an updated hardware driver. If you are unsure what the report is telling you, go to our forum and ask one of the many knowledgeable geeks in there, they’ll be happy to help!

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Lowell Heddings, better known online as the How-To Geek, spends all his free time bringing you fresh geekery on a daily basis. You can follow him on if you'd like.

  • Published 12/16/09

Comments (13)

  1. Roi

    When I right click cmd.exe and choose Run as Administrator, the command prompt opens in System32 so it actually saves the file in C:\Windows\System32
    How did you get to run cmd in the user the directory?

  2. akash

    @Roi

    There are many different ways; for example:

    Method 1
    Start -> cmd -> crtl+shit+enter to run as admin.
    enter the command “cd %userprofile%” and the terminal will point to your user directory.

    Note: the method of %string% can be used to change directory to any environment variable named string. You can change directories using this method from within a terminal or through an windows explorer window (also works in the open/save dialog)

    Method 2
    Edit the registry to change the default directory of an admin session of the terminal.

    Method 3
    Edit your environment variables.

    NB:
    methods 2 and 3 shouldn’t be done unless you know exactly what you’re doing as it could cause problems for other applications.

    method 1 is temporary; if you exit from the terminal and start a new one, it’ll point to the system folder

  3. Xsever

    I have been able to open the generated HTML file before, but not lately.

    What happens is that the file seems to be corrupt. I cannot open it with Firefox/Chrome/IE, I cannot copy it to another computer, and I cannot do anything with it.

    Any suggestions?

  4. Bobbylight

    I couldn’t open this as an HTML file either, I just had to right click and open with notepad, words were a bit scrunched up but o well.

  5. Matt

    I just ran the command on my Win 7 x64 machine and was able to open the report with IE w/o any hiccups… It’s a simple html file, so any browser should be able to open it…

  6. Steve

    FYI. It saves to the c:\windows\system32 dir and there seem to be permission issues with opening the file. I don’t know if this is due to executing IE or Firefox in non-admin role or something else.

    If you cut and past to desktop you can open it with any browser.

  7. Xsever

    Very weird. I can now open the file normally. I was not able to do that a couple of weeks ago no matter which trick I pulled out of the basket.

    I guess there was something not allowing the file to be seen/opened.

    Thanks a lot everyone.

  8. Ramzi Kudera

    I had a problem in opening the HTML file, I solved it as follow:

    1- I opened the HTML file with Notepad, what you would get is the HTML code, I copied this code
    2- Open Frontpage 2003, Past the code under the “code” view, went back to design view and that is, I got a full view of the missing HTML, you can save it if you want

  9. Bob Bobson

    I got this “helpful” notice:

      “The system will consume less power when the average processor utilization is very low.”

    Gee, you think? That’s not very useful if you ask me. Of course the system will use less power if I’m not using it, but then I may as well just turn it the hell off.

  10. Scott Howser

    To diagnose and fix Sleep issues use
    Powercfg -requests (to list items that are keeping PC awake)
    and
    Powercfg -requestsoverride (to stop items that are causing the PC to stay awake)

  11. Sean

    FIX >> Move the file out of system 32 directory eg. to desktop

  12. Luis B

    I just created a batch file to make the evaluation process more convenient.

    1 – Create a blank text file and copy-paste this code:

    @echo off
    powercfg -energy
    .\energy-report.html

    2 – Save file, then rename the .txt file extension to .bat

    3 – Run it.

    After the required 60 seconds, it will save the HTML file in the same directory where the batch file is placed, and also open it automatically, so that you don’t have to search for it. Customize the output path by editing the third line. Remove the text “energy-report.html” to prevent it from opening.

  13. reboot_68

    Seriously!!!….WTF is making Windows 7 so complex to turn on and off these power features? I mean this is ridiculous that you almost have to be an IT just to make yor compter go to sleep or hiberbate after a certain period of time! Honestly..im thinking about dumping 7 and going back to vista or even xp,it just seems this stuff should be getting more user-friendly instead of the other way around!

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