Hidden differences between system power plans in Windows?

Question

I was wondering if—aside from the settings listed in the Change advance power settings—do the pre-made power plans change any other hidden settings like throttling, CPU clock speed, etc?

For example, if I change all the settings for Balanced to be the same as High Performance, would they be identical?

There are a few similar questions here:

• Custom Windows Power Plan Issue: No one answered.

• Hidden properties of power management: Another one that mentions power.cfg, but it's for Windows 7. Windows 10 changed a lot of the power settings so not sure if it still holds.

Solution

Yes, there are indeed many power plan attributes that are not exposed in the UI. The system stores the three default power plan templates in the registry, and any modifications or custom plans are stored as overrides to the template. Any setting not shown in the UI is inherited directly from the template. One of the hidden settings, 'Personality', will tell you which of the three templates it is.

High performance will keep cpu clocks at near-max even when idle, wasting power and producing heat (servers probably use this). Power saver will stay at lowest clock speed unless under sustained high load, so your ingame framerate and video playback will suffer (might be good for laptops on battery power). Balanced is the only practical choice for normal use, since it will rapidly adjust the cpu clock according to current demand.

The defaults for processor power settings are at HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Power\PowerSettings\54533251-82be-4824-96c1-47b60b740d00. There's a FriendlyName and Description on every key, but some are not very helpful. The MSDN article for win7, "Processor power policy on Windows", describes the Processor power management section.

Searching for some of the setting names on the web turns up more interesting info. The blog post "How to Unlock The Hidden Features of Processor Power Management" reveals that the settings can be un-hidden from the UI by altering the Attribute option in the template:
powercfg -attributes Group_GUID_Here Setting_GUID_Here -ATTRIB_HIDE

I went through the registry tree and wrote a script that unhides the hidden ones: powercfg-win7-all-settings.bat. One oddity is that the Personality setting will not show in the UI even if unhidden. Also, note that the options window will look really ugly if you unhide all the settings. That's why there's the bit in the script that lets you hide everything again.

Obviously, Microsoft doesn't want users casually fiddling with these settings because there are a lot of non-obvious side-effects to changing them, and they may be heavily interdependent. On the other hand, picking the wrong power profile template has a huge impact on system behavior (performance, power usage). The user will think that they've seen all the options the UI has to offer. Meanwhile, their computer will run slowly, or keep overheating, and they won't be able to tell why.

Comments

[DavidPostill]

Please read the question again carefully. Your answer does not answer the original question.

[Emil Nechifor]

Actually it does..."if I change all the settings for Balanced to be the same as High Performance, would they be identical?" - My answer yes. PS: powercfg.exe still runs in windows 10 anniversary edition...(I use it on an elevated prompt)...see on Wikipedia for each parameter: en.wikipedia.org/wiki/Powercfg

[DavidPostill]

"My answer yes" - You don't actually say that anywhere in your answer...

[vlad zouth]

If I am reading this correctly, /processor-throttle-ac and /processor-throttle-dc are powercfg settings which does NOT show up in the advanced power settings. So the answer would be no right?

[vlad zouth]

Also, what are the default settings for /processor-throttle-ac and /processor-throttle-dc? powercfg /q is not listing them.

[iBug]

You should open "Advanced Settings" for the power plan and navigate to "Processor Power Management" where you will see that in "High Performance", the "Mininal Processor Power" is 100%. This the the actual cause for CPU to run at full freq even when idle. Change the value to 5% and observe it yourself.

[theultramage]

In High Performance mode, even if you set Minimal to 5%, the CPU will not go below 80% clock or so, because of the 20 other settings. Or at least that's what I recall from when I was investigating this back then. It's been a while, I hope I'm not mistaken. Similarly, in Power Saver, even if you set the range to 5%-100%, only sustained cpu-intense stuff like winrar/prime95 will make it go high - a typical older gpu-based game will not even register. There might even be some sort of negative feedback loop going on.