The iPhone's A6 SoC is a Custom Apple Core
Despite what previously published reports had said, the iPhone’s A6 chip isn’t the first ARM Cortex A15 processor in public usage. According to AnandTech
, the CPU is entirely different and perhaps even more significant is the fact that it is a CPU core of Apple’s own design. The A6 is the first Apple SoC to use its own ARMv7 based processor design. The CPU core(s) aren’t based on a vanilla A9 or A15 design from ARM IP, but instead are something of Apple’s own creation.
Just to make it clear, the A6 is still based off of ARM’s designs but it isn’t an ARM specific CPU design like a Cortex A8, A9, or a new A15. What this means is that Apple can customize the chip’s performance to its needs rather than pushing it or pulling it into ARM’s designs. Qualcomm previously did the same thing with its Snapdragon processors and many others are doing the same.
This marks the first time Apple has gone away from a standard CPU processor design though. Anandtech also suggests that Apple used a slightly upclocked PowerVR SGX 543MP3 GPU on the SoC to achieve the “2x Graphics” stat that the company has been boasting. Typically the Cupertino California company underclocks higher end processors depending on usage profile but this time, they supposedly went with the opposite. The company seems to have found a sweet spot for balancing the battery life and performance though, at least from what we know based on the announcement at the September 12th event. We’ll find out for sure when the device is released to the public and breakdowns start surfacing.