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So what does the new iPhone’s 64-bit processor really do for you, anyway?

Check out our review of the Apple iPhone 5S smartphone.

The iPhone 5S runs on Apple’s A7 chip, the world’s first 64-bit processor. Every other phone has a 32-bit chip inside it. That makes the iPhone 5S twice as fast and great as everything else, right? Double the bits, double the fun? Well, not exactly. The answer, of course, is little complicated. Apple’s decision to go 64-bit with the iPhone 5S does deliver real world benefits today – but it’s also about setting the stage for the future. Here’s why Apple has made a smart investment, and how it affects you.

What’s so special about 64 bits?

If moving from a 32-bit to 64-bit architecture seems like a history repeating itself, you’re right. Both desktop computing and game consoles have gone through similar transitions, with mainstream traditional computers going fully 64-bit in the last few years and game consoles hitting it in the late 1990s.

There are three benefits to a 64-bit system:

  • You can have more than 4GB of RAM
  • Faster speeds, better performance
  • Advanced features

RAM: One pressing reason traditional computers moved to 64 bit was to use more RAM (Random Access Memory) – that fast workspace memory that’s separate from disks, flash, and other long-term storage. Basically, a 32-bit number can handle up to 4 gigabytes (GB) of RAM – and this limit also impacts handling very large files, like movies and raw video. Back in the 1980s when 32-bit processors became a standard, a 4GB ceiling seemed tremendously forward-thinking, but by the mid-2000s desktop power users needed more. Chipmakers came up with workarounds to let 32-bit systems handle more memory, but also made the transition. These days, computers are mostly 64-bit – and come with at least 4GB of RAM. A 64-bit processor does not double RAM capability compared to 32-bit systems: it multiplies it by 2³² to a theoretical maximum of 16 exabytes. An exabyte is a billion gigabytes, so, again, the limits seem tremendously forward-thinking.

iPhone 5S AnnouncementSpeed: Oddly, A 64-bit chip won’t necessarily out-perform a 32-bit chip. Since 64-bit systems use twice as much data for many low-level operations (shuffling 64 bits instead of 32 just to read a number, for instance), they need more memory and can even be slower than equivalent 32-bit systems. Something like this actually happened a decade ago with Apple’s first 64-bit Macs. These days, 64-bit chips are a lot better. Newer 64-bit devices almost always have real-world performance improvements over 32-bit.

Fancy features: Every chipmaker packs in fancy features to distinguish their products from everyone else’s. For instance, Intel’s Sandy Bridge and Ivy Bridge processors have built-in support for encryption as well as for encoding and decoding video. Apple’s A7 chip is based on the ARMv8 architecture, which is not only backward compatible with previous 32-bit applications (meaning, every iOS app written before the iPhone 5S) but it also offers built-in encryption and TrustZone, a security model that allows for two virtual processors. Trustzone creates a “normal world” for your regular phone activities, and a separate “secure world” that’s encrypted on the processor, making it difficult to attack data stored there, even if you have possession of the device.

How does 64-bit help Apple?

Here’s how going 64-bit makes sense for the iPhone 5S, and for Apple’s mobile devices going forward.

Memory: Mobile devices aren’t facing the 4GB barrier yet. (Game consoles weren’t either: the Playstation 4 and Xbox One will be the first to ship with more than 4GB of memory.) The Samsung Galaxy Note 3 currently has the most RAM in a mobile device, packing in 3GB pretty much just so Samsung can show off. In comparison, the iPhone 5 – along with the new iPhone 5C and iPhone 5S – sport only 1GB of RAM. The iPhone 4 and 4s have 512MB. One reason for that is that RAM has to be on all the time, consuming precious battery power. Right now, Apple does not need a 64-bit chip to handle memory.

However, the iPhone and iPad may reach or surpass the 4GB threshold in the next two or three years. If so, developers will have been building 64-bit iOS software for years by the time iPads, iPhones, and any other iDevices have require a 64-bit architecture. That’s a good way to ensure a seamless transition for customers.

Speed: The iPhone 5S does get performance benefits from going 64-bit. Early results from iPhone 5S review units tested with Primate Labs’ Geekbench tool (nods to private sources, AnandTech and Daring Fireball) for measuring processor performance show:

  • The iPhone 5S 64-bit mode outperformed 32-bit mode by up to 25 percent. That means most apps will get a free performance boost just for recompiling to 64-bit.
  • The iPhone 5S processor is about twice as fast as the iPhone 5 in everything but memory access (that’s 1.4x faster).
  • The iPhone 5S about 25 percent faster than the iPhone 5 for everyday Web browsing (some Javascript tests are twice as fast as 5).

“Converting to 64-bit offers a performance improvement on the order of 10 to 20 percent,” said Kevin Krewell, senior editor of Microprocessor Report. “The part that isn’t separable is that we have a new chip in the A7, and the A7 is much faster than the A6. Just the architecture of the chip has much better performance, in and above the change to 64-bit.”

iPhone 5S CPU Performance

The 64-bit A7 isn’t just a marketing stunt. It delivers real performance benefits for apps right now. Apple builds further on those benefits by converting all of iOS 7 to 64-bit for the iPhone 5S – and for any future 64-bit devices (cough iPad 5 cough) that come along. That means iOS 7 – along with core apps like Safari, Mail, Photos, Maps, and Siri – all wring the most benefits from 64-bit performance, and some of those components improve performance for third-party apps as well.

Fancy Features: The 64-bit architecture used in the A7 makes Apple’s new Touch ID fingerprint scanning technology possible, thanks to its encrypted on-chip security. Sure, a few smartphones have offered fingerprint readers (like the Motorola Atrix 4G) but no one has pushed the technology to the level Apple’s trying to achieve. Touch ID not only has a sophisticated biometric sensor, but Apple is integrating (optional) biometric security deep into its processor. That’s unprecedented. It also means Touch ID will never be available for 32-bit iOS devices – it’s a high-profile, front-and-center feature that’s 64-bit only. Assuming Touch ID survives countless attacks (from both security experts and hackers) and everyday users embrace it (early reviews are promising), expect the tech behind it, called Secure Enclave, to become central to the iOS experience. Coming next: Passbook and mobile payments.

What will 64 bits bring us next?

There are a lot of benefits to 64-bit processors. When we need more memory, we’ll have it. The traditional example of a memory-hungry apps is always intensive games like Infinity Blade, but video is another. Photographers and filmmakers are already using tablets to take preliminary passes on raw footage before loading them into full-fledged desktop video editors.

If Touch ID and Secure Enclave succeed, expect Apple or third party developers to build on them. Apple could extend Touch ID to things like parental controls and require authentication to access specific apps (like Mail) or data (like your Photo Stream). Eventually third parties will be able to use Touch ID: the Amazon app could require authentication before letting an order go through, or banks’ mobile apps could require a fingerprint before authorizing a transfer or payment. Apple could also extend Secure Enclave to encompass more than fingerprint hashes or payment info.

iPhone 5S Touch IDGoing 64-bit also offers more computing power, so apps that do serious number crunching can benefit strongly from the new architecture. Examples could include real-time music and video applications, such as software synthesizers, recording and mixing apps, ear trainers (great for learning an instrument), video editors, and apps that process and apply effects to audio, images, and video in real time. Another potential benefit is virtualization: although Apple is unlikely to allow (say) iPad users to boot a separate Android VM within iOS, virtual technologies could make it possible to create a separate sandbox for untrusted apps – so maybe you could use that new social app without fear of it rummaging through your contacts, email, or IMs. Developers should also have an easier time sharing code between iOS and OS X.

Although the A7 is Apple-only, it’s based on architecture by ARM, which is licensed to many chipmakers (all phones use ARM chips). Other 64-bit chips based on the ARMv8 architecture will come to Android in the next year to 18 months, complete with built-in encryption and TrustZone. If Apple’s Touch ID succeeds, other chipmakers will build authentication and mobile commerce solutions – they might even define an industry standard and leave Apple behind. And there’s no reason authentication technology has to be limited to fingerprints: that’s just the sensor Apple liked. TrustZone and integrated encryption can secure data from voiceprints or facial recognition. It can also be used for credit card processing and mobile payments, or to securely access to other technologies like NFC or Bluetooth, perhaps to use a smartphone as a wireless key.

No matter what comes next, it’s exciting to see Apple embracing what will soon become a new standard for processors.