The iPad 2 is just a few months old as of this writing but already the rumors are starting about what the next version of Apple's best selling tablet device might have inside. The Barron's web site has a report that speculates that the iPad 3 will have a quad-core processor inside. Furthermore, the speculation is that the iPad 3 will have the exclusive on that quad-core product.
The report cites comments from Linley Gwennap, the senior editor for the print magazine Microprocessor Report. He states that it's "safe to assume" that the next processor for the iPad 3 will be the A6 chip and that chip will have four processor cores. Nvidia is already demoing its upcoming quad-core mobile processor, code name "Kal-El" with plans to introduce it in products such as tablets later this year. The speculation is that the iPad 3 would have to have four cores just to stay competitive.
However Gwennap also speculates that the A6 chip might run too hot to be used on the smaller iPhone design. That's why Gwennap also says that the iPad 3 might have an exclusive on the four core processor with the 2012 version of the iPhone getting a different chip inside, perhaps a smaller version of the iPad 2's current dual-core A5 chip. It's widely speculated that the upcoming 2011 version of the iPhone will use the current version of the A5 chip that powers up the iPad 2.
One other interesting bit from the article is Gwennap's claim that "33 square millimeters of the A5 is extra circuitry that can’t be accounted for." According to him there's no reason for this and he says, "Without information from Apple, determining all the reasons for the A5′s larger die is impossible."