There's a lot of speculation about what's inside the A4, Apple's custom and ultra-power-efficient chip that powers the iPad. Nobody knows for sure because, like all their products, it's a seeeeeecret. Until now.
According to Jon Stokes' well-trusted sources, there is no Cortex A9 dual-core inside Apple's A4, but just a single Cortex A8 and a PowerVR SGX GPU. According to Jon, it's probable that Apple has taken out a lot of the communication, image, and video blocks that the Cortex A8 uses, making it an extremely lean and efficient processor.
Do you have to care about this? No. As Jon says, the important thing about the iPad is not its specs and how many polygons it can push or how many cores it has. That doesn't matter to normal consumers—that just matters to feature-list-obsessed geeks.
What is important for consumers is that the iPad provides an smooth experience, using a new user interface paradigm. As Jon points out, what's important about the iPad is that it may be the new Wii. Just like Nintendo's console opened gaming to a huge amount of normal consumers who don't have their brains wired to a game pad, the iPad may do exactly the same, simplifying computing for that giant and silent majority of users who dislike or don't really understand the current user experience of Windows and Mac OS X. [Ars Technica]