[dbwoo]

why is there such a big difference in boot time between ac vs dc?
plug into charger = 35 sec
on battery = 105 sec

[Ninjatogo]

Maybe RIM has set it to boot with one core set at a slower clock speed when using battery to save energy. For many devices the boot-up process can drain the battery quite a bit, much more than regular use. On my Bold 9000, I can go for hours of regular use and only go down two bars of battery, but a simple cold boot-up on battery uses up the same amount.

I'm guessing they have set the Playbook to boot with both cores running at a higher clock speed when plugged in.

[peter9477]

Just tested with 2.0.0.3894. In the past we'd measured it as slightly slower to boot up than 1.0.7, presumably because of debug code.

1. turned power off
2. waited 15-20 seconds
3. pressed power button and noted time
4. saw logo screen come up and noted time
5. saw home screen come up and noted time

On the charger (and actually charging): 31s power button to logo, 13s more till home screen (total 44s)

On battery: 13s button to logo, 71s more till home screen (total 85s)

Tried the charger one a second time: 26s to logo, 17s till home screen (total 42s)

Tried battery a second time: 16s to logo, 71s more till home screen (total 87s)

I don't know yet why being on the charger makes it take longer to get to the logo, but presumably the reason the overall startup is so much faster is because the CPU is running at a lower clock speed when it's on battery, to conserve energy.

I actually suspect that's false economy, since having the screen and backlight on takes so much power that we'd be better off if the CPU was maxed out during the bootup, just to decrease the overhead of having the screen lit for so long, but I don't have data on the relative power consumption of different CPU clock speeds and RIM does...