My Power Options on my HP Envy 17 (i7) are set to keep a "Maximum processor state" of 100% when plugged in or on battery:
But when I unplug the laptop, The Turbo Boost Monitor and Processor ID Utility show the processor dropping from 1.85 GHz to 0.17 GHz.
Unplugged, on battery only:
And of course it gets ridiculously sluggish. Am I missing something here? Why would my processor tank when it's still set to max out at 100% when unplugged?
Well for starters your cooling policy on battery is passive, you could try setting this to active. Active cooling uses the fan to cool the CPU, passive cooling uses CPU throttling to keep the CPU cool. There could be other throttling mechanisms at work too but give that a try first.