Apple May Have Used Custom Designed CPU Core For iPhone 5’s A6 Chip

When Apple unveiled iPhone 5 at the media event on Wednesday, it announced that it was powered by their next generation A6 chip, which Apple says is twice as fast as A5 chip that powers iPhone 4S. The A6 chip also offers graphics performance that’s up to twice as fast as the A5 chip.

However, Apple didn’t mention the number of cores, nor did it mention the clock speed.

Few days back, AnandTech had speculated that since Apple reserves major Ax SoC number iterations for architecture changes, it indicated that Apple has used ARM Cortex A15 processor cores as it is the next major jump for ARM architecture. Apple used Cortex-A8 processor cores in the A4 chip that powers iPhone 4 and Cortex-A9 processor cores in A5 chip that powers iPhone 4S.

But AnandTech now reveals that Apple seems to have used use its own ARMv7 based processor design – basically a custom designed CPU core for iPhone 5’s A6 chip.

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.

AnandTech notes that Apple may have created its own ARM based CPU core by licensing the ARM instruction set architecture rather than licensing ARM’s Cortex A15 core as the original design goal for ARM’s Cortex A15 was targeted at servers.

Rumor has it that the original design goal for ARM’s Cortex A15 was servers, and it’s only through big.LITTLE (or other clever techniques) that the A15 would be suitable for smartphones. Given Apple’s intense focus on power consumption, skipping the A15 would make sense but performance still had to improve.

We’ll still have to wait for iPhone 5 to be disassembled to get a confirmation on the number of cores and benchmark tests to find out the clock speed, but AnandTech speculates that A6 probably has two cores. The fact that Apple didn’t trumpet the number of cores as it did when A5 chip came with dual-cores, seems to strongly indicate that they’re right.

When Apple acquired P.A. Semi (in 2008) and Intrinsity (in 2010), it was widely speculated that Apple could use the expertise to deliver specialized processors and chipsets to differentiate its mobile product line from other smartphone vendors who directly license ARM’s CPU core.

Back in 2011, it was reported that Apple has 1000 engineers working on chips, which are a vital part of the “Post-PC” future Apple is betting on.

[via AnandTech]