Computer chips usually tend to grow smaller with time, but with the A5X, the processor in the new iPad, Apple has gone in a different direction. It’s actually larger than its predecessors.
John Brownlee, Cult of Mac:
Though they are built upon the same 45 nanometer architecture, the A4 chip was only 53.3 mm square. Now compare that to the A5X, which measures in at a whopping 165 mm!
The extra girth comes from the four cores of graphics powering the beautiful Retina Display.
Brownlee says the size of the A5X is the reason you won’t see the A5X in the iPhone or the iPod Touch, “…the smaller device doesn’t need that much graphics chutzpah, and even if it did, it couldn’t fit a chip this size inside its already jam packed innards anyway.”
There are more images and a full breakdown over at Chipworks.