Apple eyes ARM for future Macs

Rumour has it that Apple is planning to shift its Mac line back to RISC processors, ditching Intel for industry darling ARM - but would it really make such a major change so soon after adopting CISC?

Our colleagues over at ITProPortal say that Apple has earmarked a whopping $3.9 billion on bringing the dream of Project Aquarius to life, 25 years after the idea was first approved by the company's management.

Back in the dark days of 1986, Apple started Project Aquarius as a way of updating its Motorola 68000-based machines with new hardware - a four-core RISC-based chip. While that heady aim was never achieved - Apple opted to go for IBM's PowerPC line instead, and then dropped RISC altogether in favour of CISC processors from x86 giant Intel - Apple's growing interest in the works of British chip designer ARM suggest that it could be getting resurrected.

It's a theory that makes a certain amount of sense: Apple has developed its own ARM-based A4 processor based on the Cortex-A8 design, which it uses in its iPhone and iPad products, meaning it's got the engineering expertise to pull off a complete transition.

Further, it's got the experience: five years ago, the company announced that it was ditching IBM's PowerPC architecture to use the faster, cheaper x86 processors from Intel - a move which meant that all software had to be rewritten to support a CISC, rather than RISC, architecture.

For those who think that ARM's low-power designs are unsuited to the high-performance demands of modern desktop computing, think again: ARM's latest creation, the Cortex-A15 'Eagle,' includes many performance-boosting features aimed directly at desktop and server use - plus a reference design clock-speed of up to 2.5GHz.

A four-core chip based on a Cortex-A15 design running at 2.5GHz would certainly give Apple's purported Mac Aquarius a running start in the performance-per-watt stakes, but could it really be looking to ditch Intel so soon?

With just five years having passed since Apple forced its developers to retrain on writing programmes for the x86 instruction set instead of the old familiar PowerPC architecture, it's hard to imagine that the company would ask its developers to rewrite for yet another architecture - and while an abstraction layer would allow backwards compatibility with older software, as during the PowerPC to Intel transition era, programmers would still need to rewrite large portions of the code at Apple's behest.

Despite the company's almost cult-like following, that's something which would likely make a lot of its followers extremely unhappy - but there could be a plus side to the move.

With Apple already using ARM-based processors in its mobile devices, a move to the same architecture on the desktop would allow developers to produce binary-compatible packages for use across the entire Apple ecosystem: single programs that would work on desktops, laptops, mobiles, and tablets.

Better yet, it would allow Apple to merge the iOS App Store and the Mac App Store into one giant software repository. While some applications, such as those that rely on the target device having smartphone functionality, wouldn't translate to the new universal app model, many others would - and offer developers a far larger market for their wares.

With Apple keeping quiet on its plans, it remains to be seen if Project Aquarius will truly be achieving its aim, 26 years after the idea was first raised.