Not all iPads are made equal, even if they're all packaged and branded identically. There's a major new mutation within the 2nd generation tablet and it brings significantly better battery life. Specifically, the fourth and latest production model of the iPad 2 (known as iPad2,4) has not only a lower price tag ($399) but also a new 32nm processor, which is significantly smaller and more efficient than those in previous iPad 2s (which had 45nm chips and an older transistor design). According to AnandTech, this results in an overall 16 percent
