The following solved it for me....
To do it via the Power Options, right click the battery icon (or electrical plug icon) in the lower left corner of the screen, then...
1. Select a power plan and then click "Change plan settings"
2. Click "Change Advanced Power Settings"
3. Look for "Processor power management" and expand it
4. Expand "Maximum processor state"
You can now enter the percentage usage of the CPU while on battery and plugged in.