Check Power Throttling in Task Manager

Even if you reset Power Options in Windows Settings or Control Panel Power Options, it can be automatically reset by Windows updates or other applications.

There is a much quicker and more direct way to see if Windows is throttling your cpu power in Task Manger (CTL ALT DEL).

In Task Manger select the Details Tab.

Next right click on any top column and select "Select Columns" and scroll down and checkmark 'Power Throttling'.

1) Now every time thereafter you open Task Manger, the Details tab will automatically show the Power Throttling column. Every executable program (.exe), such as flightsim.exe, should be labeled Disabled in that Power Throttling column. If they aren't, then change them all to Disabled.

2) And then go into Control Panel or Windows Settings and redo your Power Options / Change Plan Settings / Change Advanced Power Settings / Processor Power Management / Minimum processor state & Maximum processor state to 99% or 100% (opinions vary whether to use 99 or 100).

2) Is a long process and may have been reset behind your back. Using 1) is a much quicker way to check if Windows is right now throttling cpu power.