According to the teardown, the chip has a 12-cluster GPU, two CPU cores, and is missing the level-three cache memory of the A9 chip. Chipworks also revealed that the chip is approximately 147 square millimetres, which is 40% bigger than the TSMC-built A9 chip inside the iPhone 6s and 6s Plus. The Motley Fool adds that this massive increase in size probably means that the chip is even harder, and more expensive, to manufacture than previously. This could be why Apple didn’t include the level-three cache, which may not have provided enough of an increase in performance to justify the added expense on top of an already difficult build.
As Motley Fool notes, the A9X could be said to be the “most advanced mobile system-on-a-chip” currently available, with the best CPU/graphics performance of its type.
Source: Inside the Apple Inc. A9X Chip -- The Motley Fool
