I'm using Intel GPA on a Surface Pro 2 to measure power usage on an application and I've spotted something that I can't explain. If I (using the same power profile) unplug the power cord when profiling the power usage *goes up*. How is this possible? I'd expect power to remain the same, or maybe go down (in case there's some HW limitation kicking in when not plugged in), but for the Processor Package power usage to go up when the power cord is unplugged is deeply mysterious.
Can anyone explain what's going on? What should I use for comparisons, plugged or unplugged?