Creating a Power Efficiency Report in Windows 7
If battery life on your laptop or power consumption on your desktop is a concern, you can have Windows 7 create a Power Efficiency Report to help you tweak all types of power-related settings. Once you run the command it will analyze various components and settings for about a minute. Then you can open the detailed HTML report and see what it recommends to change.
To create the report, open Command Prompt as an administrator and use the following command:
powercfg -energy -output PATH/FILENAME.html
Then navigate to the report and open the HTML file.