Luckily there are battery stats. On a 7840U with power-profiles-daemon installed and PCI power saving turned on (but not wifi or audio power saving, or VM write

Luckily there are battery stats. On a 7840U with power-profiles-daemon installed and PCI power saving turned on (but not wifi or audio power saving, or VM writebacks, I don't feel those are worth the power savings), it draws 3W if I'm doing absolutely nothing with the screen on its dimmest setting (I mostly use the laptop in bed at night), and 5-11W while web browsing on Firefox. It goes up to about 13W while watching youtube, even though it claims hardware accelerated video decoding is on.