Updated core management software in the new beta includes an "/cores/core.3" option which represents a fourth available processing core. The core references begin at "/cores/core.0" for a single core processor.
We cannot conclude that due to iOS 5.1 including quad-core processor references, Apple's next-generation iPad and iPhone will include a quad-core chip, but it seems reasonable based on Apple starting with a single core chip in 2010 and moving to dual-core in 2011. A quad-core chip in 2012 would fit the pattern. On the technical side, Apple is already rumored to be working on a quad-core "A6″ processor, and such processors were said to be ready in 2012.
A quad-core A6 processor would provide a significant performance boost and help the next generation iPad power its widely expected Retina Display. It would also allow for improved gaming, smoother system navigation, and more powerful applications.
Below you can see a comparison of the iOS core management software from pre-iOS 5.1 beta and iOS 5.1 beta. The dual-core A5 chip is the one marked with "core.1"; whereas, the new chip is marked with "core.3".