I just spent some time freaking out over my Power Options. I know how to add advanced Power Options (for CPU Management) to disable core parking (or so I thought...), but then I noticed that changing values within the registry, shutting down fully, and restarting PC did NOT change the values within Power Options controls. Changing values in Power Options, shutting down fully and starting up, was also NOT changing values in registry even after a complete shut down. Then I figured it out and it now freaks me out. I enabled advanced Power Options using HKEY Local Machine registry entry. That did make advanced CPU management OPTIONS/SETTINGS show up in Power Options. However, when I changed VALUES for within those CPU management options, they were affecting the USER level registry values, while Local Machine registry values remained the same! To make it easier to understand: A Local Machine registry tweak enabled GUI Settings, but changing values within those GUI settings was affecting User registry, not Local Machine. How do you go about it? I noticed that this isn't the first time it happens. Then you also have to consider the programs that affect registry entries - how do you know which registry entries they affect? The Local Machine ones or the System ones or the User ones???
I suspect it is by design. I have long known changing the settings in registry does not reflect in the GUI.
Well that's the issue - it sometimes does and sometimes doesn't! How do you when it does and when it doesn't and why?
I can't speak for power options, I do a few tweaks to show hidden power options and those show up right away but I don't edit power setting values via the registry. It really depends on the application, values from the registry are always being read for particular actions and sometimes the registry is read when a application or service is started and not while it's running. Explorer is always reading the color settings when manipulating windows so if I change it in the registry they take effect right away, many other Explorer settings when changed in the registry do reflect in the GUI settings but probably won't take effect until SHChangeNotify is called, which won't occur if the registry is edited directly instead of applying the option through the GUI. In that case Explorer will have to be manually restarted.
I've seen OEM's using powercfg.exe in their scripting to modify power schemes. That's probably the route to go...