Defrag Tools #168 - Powercfg Sleep Study

In this episode of Defrag Tools, Andrew Richards and Chad Beeder talk to Nashaat Soliman and Paresh Maisuria (program manager and developer from the Windows kernel power team) about the "Sleep Study" feature in the Powercfg tool, and how you can use it to diagnose battery drain issues on Modern Standby systems.

For related content on power management and analysis using Powercfg, refer to the following earlier episodes:

For additional details on Sleep Study, see this blog post:


[00:00] Welcome and introductions
[02:55] Powercfg Sleepstudy requires a system capable of Modern Standby. What is this compared to traditional standby?
[07:03] You can specify a report duration (up to the last 28 days) and look at the resulting report file
[08:57] %Low Power State Time columns indicate how much the system was in the lowest power state during each standby session
[10:13] Click on a table row for details, including a chart of how often the system was woken up to do work
[15:38] Top Offenders list of who woke up the system
[17:15] Nashaat's system is an engineering sample which includes a special Energy Meter chip to enable more accurate power usage data (Jorge Novillo mentioned this in Episode #157 as well). Useful in debugging preproduction hardware.
[18:46] Example 1: TV capture device keeps the system from entering standby
[21:01] The list of devices we monitor, which are expected to be powered down during standby, is in a firmware table provided by the system manufacturer. We can see these in the report.
[25:44] Example 2: Standby settings configured incorrectly on the system. The Sleep Study report shows idle standby was disabled.
[29:29] Example 3: A particular desktop app which prevents us from entering standby for 5 minutes
[32:09] Pros and cons of Sleep Study vs. manual analysis via Windows Performance Toolkit

Questions/Comments? Email us at defragtools@microsoft.com