Get the inside story on how your PC is managing power
One of the most powerful diagnostic tools in Windows doesn’t have a graphical interface.
The Powercfg command, which is available only from a command line, allows you to manage, save, and export power settings. But its best trick is the ability to produce a detailed report of energy usage on your PC, including clues about devices or services that are preventing your system from going to sleep when it should.
To produce the energy report, open an administrative Command Prompt window. (From Windows 8.1 or Windows 10, right-click Start and then click Command Prompt (Admin).)
At the command prompt, type cd %temp% and then press Enter to switch to the Temp folder, where your report will be saved.
Enter the command powercfg /energy to begin generating the report. The process monitors your system for 60 seconds and then analyses the results, saving the report as a document called energy-report.html in the current folder.
To open that report in your default browser, just enter the command start energy-report.html .
Information courtesy of the excellent Techrepublic.