Actually, that Acer has six hours of battery because it uses an impressive battery...
Something like 2x the power of the battery of the iBook...
87w and 7800mAH!!!
The PowerBook 17" uses a 65w power adapter..
And the iBook a 45w power adapter..
The Dual Core Yonah, will be faster, but looks like it will be power-hungry..
Anyway, there is a better version of Yonah, not at 2Ghz, anyway, i will be satisfied with a low-voltage dual core 1,66Ghz Yonah, wich will be like a G4 in power consumption..
It also could be the ATI X1600 512Mb what needs so much power..
It's obvious that this isn't a light notebook, looks like more a desktop replacement but with a 15,3" screen instead of 17"..