powerd effectiveness

[Darren Pilgrim]

I guess I should chime in here:

1.6GHz Pentium M notebook.  Everything enabled: ACPI, USB, wireless,
bluetooth.  powerd_flags="-i 100 -r 25"  The backlight is on continuously in
FreeBSD.  Lag is hard to notice, since it takes <100 ms to make the
100->1600 MHz step, but I can see brief lag if the machine is completely
idle and I do something to eat the CPU that provides an immediate visual
indicator of churn rate, like run an animation.

Battery life:

FreeBSD, powerd running: 4.5-5 hours
FreeBSD, powerd not running: ~2 hours

For comparison:

Windows XP, aggressive power-saving: ~3 hours

As for heat, the surface hot spots all stay significantly cooler with powerd
running.  I don't have working system health stats in FreeBSD, so
quantitative heat reports aren't possible.