updated 10:05 am EST, Fri January 6, 2012
iOS 5.1 references four cores
A delve into the iOS 5.1 beta has supported beliefs that the A6 chip will have four cores. Its processor management software was seen by 9to5 as referencing "core.0" through "core.3," a giveaway that it has to control quad-core hardware. iOS 5.0 only stops at "core.1" and hints Apple is at least using iOS 5.1 as a testbed for quad-core devices, if not as the initially shipping version.
The discovery, if borne out in shipping hardware, would end doubts as to the nature of the A6. Although it was a common assumption that the 2012 chip would be quad-core, Apple's manufacturing contractor Samsung is itself upgrading its dual-core design and doesn't appear to have immediate plans for a quad-core chip of its own.
Like on desktops and notebooks, quad-core isn't always faster and depends on the software fully using four cores. Samsung's future chip, at 2GHz, could be faster in some circumstances than an A6 if Apple doesn't come close in practical speed per core. However, Apple has typically been aggressive about optimizing for multiple cores and could see both creative apps and games running much faster with four cores than with two.
Apple in its brief history of custom processors has always put them in the iPad first and downclocked them for use in the iPhone later that same year.