Apple's 64-bit A7 chip (FAQ)


Apple introduces the iPhone 5S and its A7 processor.
Apple introduces the iPhone 5S and its A7 processor. CNET

Apple is the first to get a 64-bit processor into a smartphone. So, what's all this 64-bit business anyway?

Is this the first 64-bit ARM chip for smartphones?

The Apple A7 is the first processor from any company to implement the new 64-bit ARMv8 instruction set.

Linley Gwennap, principal analyst at the Linley Group, a chip technology consultancy, supplied CNET with the quote above, answering that question.

The "ARM" in ARMv8 refers to the dominant chip technology used in smartphones and tablets worldwide. Apple, Qualcomm, Samsung, Nvidia, MediaTek, and others all license technology from ARM. That's how Android can run on a variety of smartphones with a variety of ARM chips.

The 'v8" part refers to ARM's 64-bit chip architecture. Current ARM chips from all of the above chip suppliers are 32-bit.

Apple is ahead of the pack. "To achieve this feat, Apple must have designed its own custom CPU," Gwenapp said, referring to the 64-bitness in the CPU or central processing unit. ARM's own 64-bit designs are not scheduled for commercial production until 2014 -- and that's probably later in 2014, not early in the year.

What does 64-bit get me?
Ah, there's the rub. This same question was asked when Apple introduced the 64-bit PowerPC G5 from IBM.

The short answer is a future iPad -- or whatever future newfangled iOS device Apple dreams up -- can address more memory. Let's just say more than the 4GB limitation in many cases for 32-bit processors.

The longer answer is that 64-bit allows data-intensive applications to handle large chunks of data more efficiently than 32-bit. Right now, ARM is aiming 64-bit chips at servers, not smartphones. Why? Because servers can benefit immediately in a big way -- for the reasons stated above.

In fact, the only other ARMv8 chip that has even reached the sample production stage is AppliedMicro's X-Gene, a server processor expected to reach production late this year, according to Gwennap.

So, Apple will have to convince its own developers that it makes sense to develop 64-bit apps for consumers, like the Epic Games Infinity Blade 3 demoed at the Apple iPhone event on Tuesday.

Apple's Phil Schiller, speaking at the event, said Apple's iOS 7 has been "completely re-engineered for 64-bit...64-bit kernels, libraries, and drivers. And the apps that come with your iPhone 5S, they've been re-engineered to 64 bit as well."

"This will be an easy transition for developers, we've updated our support 64-bit," he added.

If you listen to Epic Games executives talk about the improvements that the 64-bit A7 made possible (the 38:40 mark) for their game, it's impressive. But at least some of that performance boost is coming from the richer OpenGL ES 3.0 graphics-acceleration interface and an improved graphics chip, not from the 64-bit design.

So, what does 64-bit get you? The upshot is the potential for faster apps that can juggle large amounts of data more efficiently.

When will we see more 64-bit apps?
Don't hold your breath. It's a wait-and-see scenario to see which apps jump to 64-bit quickly because of the obvious benefits -- and which don't.

Do all apps benefit from a 64-bit processor?
No. Many, if not most, apps won't see any meaningful benefit.

Will the iPad go 64-bit A7 too?
You bet. Possibly with a faster version of the A7 for the iPad. And there's probably equal or more potential for future iOS devices that Apple is undoubtedly planning.

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