Where does the extra battery life come from? The CPU? Graphics? Better RAM? Better wifi/BT? Software improvements in the OS and apps to use power more efficiently? Lower power screen?
Battery life is affected by such a multitude of components that it's hard to extrapolate savings in one component to the battery life of the complete device.
Yes, but that has nothing to do with the RAM. Processors take a significant chunk of the platform power while RAM in almost all cases does not anymore.
