This item has been corrected.
The obsessives at the hardware blog AnandTech have dug deeper than ever into the guts of the chip that powers the iPhone 5s, iPad Air and the high-end iPad mini—Apple’s “A7” chip—and what they’ve found is even more impressive than all we’ve heard up until now about Apple’s most powerful ever mobile microprocessor.
Here are some takeaways:
As Anand Lal Shimpi wrote on his eponymous blog, “At the launch of the iPhone 5s, Apple referred to the A7 as being ‘desktop class’—it turns out that wasn’t an exaggeration.”
His point is that the Apple A7 is not competing with other mobile processor chips, but rather with the Intel chips that typically go into notebooks and desktop PCs. The chips Intel makes for those machines are 64-bit, and now, so is Apple’s mobile chip. That means the size of each instruction that the chip handles is twice as big as what’s being processed by a typical mobile processor, which until now have all been 32-bit. That’s just the beginning, however—the real reason that Apple’s A7 chip is twice as fast as the A6 is that the chip has twice as much stuff crammed into it—twice as many of the individual units required for processing (e.g. two load/store units instead of one) which means it can process twice as many instructions at once.
This means Apple was able to double the speed of its mobile chip without increasing the frequency with which the chip is processing instructions, which is important because power consumption goes up as frequency increases. Apple has essentially figured out a way to make its chip “think” more efficiently—and without running down your battery so quickly.
Strangely, the iPhone 5s barely takes advantage of all this power. When Shimpi surveyed the apps that exist for the iPhone, he found very few that have been re-written to take advantage of the speed of the A7.
Simply put, an A7 chip in an iPhone 5s is overkill—which suggests that Apple has other plans for the chip. It seems unlikely that Apple would build the fastest mobile processor on the planet, years ahead of its competitors, unless it had plans to take fuller advantage of its potential.
Presumably the company will roll out yet another generation of this chip, the A8. But by then, their engineers may have devised another use for it.
Apple is close to the point that it could release a notebook computer running on its own chips—and divorce itself from Intel
Already, Samsung has teamed up with Google to release fast, useful notebook computers that run on mobile chips. It’s not a stretch to imagine that Apple is headed in this direction, too, only with chips that are much faster than Samsung’s. Why build your own “desktop class” microprocessor if you don’t plan to use it in a notebook or a desktop computer?
Apple seems unlikely to replace the very powerful Intel chips in the Mac Pro. But a Macbook Air with an extremely power-efficient mobile chip is not out of the question. Apple’s Mac OS X requires more processing power than its mobile iOS operating system, but the latest iPad is already more or less a notebook sans keyboard. Even a super fast A8 would only be as fast as Intel desktop-class microprocessors of 2-3 years ago, so a MacBook Air running on it would either have to run a more-efficient version of OS X, or offer some other advantage, like ultra-long battery life.
As Apple’s processing speeds ramp up, the overall trend is that mobile chips will eat up more and more of the market for processing power—going from smartphones to tablets to notebooks. That’s great news for the consumer, but it’s terrible news for Intel, which will now be in forced to compete with all the makers of mobile chips—Samsung, Qualcomm and others—and with Apple too.
Correction (April 1): An earlier version of this story mistakenly said the performance improvement of Apple’s A7 chip over its A6 chip was due to the move to a 64-bit architecture. In fact, the main reason the A7 is so much faster than the A6 is that it has, as firmware engineer John Potocny writes, the A7 chip “[almost doubled] all of the core components on the chip (i.e., there are now four Integer ALUs instead of two, and two load/store units instead of one). This means that the A7 can process around twice as many instructions simultaneously as the A6 can, but the improvement is simply not a result of moving to a 64-bit architecture.”