Just see the keynote again. It actually uses less resources even today as compared to Windows 7 SP1.

What kind of battery life does Windows 7 SP1 get on tablets?

The $550 Acer Iconia W500 tablet (which comes with an attachable keyboard base) got 4:06 on a Cnet video playback battery drain test.

http://reviews.cnet.com/tablets/acer-iconia-tab-w500p/4505-3...

Acer isn't exactly known for brilliant power engineering, so a better vendor could likely do better. But this also wasn't exactly a high-powered chip, either. So this is probably a plausible baseline for battery usage in Win 7.

They need to beat this by quite a bit in Win 8, or the tablets will be a tough sell.

Given that the iPad 2 gets 11 hours + in similar tests I don't think that's a tough sell, I think it's an impossible sell.

Don't know. A quick search brought up this page where the tablet gets a 7 for battery life. So I am guessing its ok.

http://reviews.cnet.com/tablets/acer-iconia-tab-w500p/4505-3...