Why 64-bit phones are going to be a big deal...but not yet

23rd Dec 2013 | 11:00

Why 64-bit phones are going to be a big deal...but not yet

Everything you need to know about the coming smartphone revolution

One brand has done it already. The rest of the smartphone and tablet industry is busy playing catch up. There's no stopping it.

What are we talking about? 64-bit processors for phones and tablets of course! It's the future for all your favourite gadgets.

But some have questioned the value of 64-bit computing for phones and tablets. Will it really bring a big boost in performance? Or is it just a futile, marketing-led specification race in a world where there's very little space left to innovate?

One of the industry's behemoths, Apple, has already made the jump to 64-bit with the mighty A7, its latest chip for iPhones and iPads. Does it know something the rest of the industry has missed? And when can you expect the Android horde and the more mobile Windows-based devices to go 64-bit?

What is 64-bit computing?

To get to the bottom of all this, we need to start with a quick look at what 64-bit computing is all about. What does 64-bit actually mean?

In simple terms, it's about how much memory a processor can actually access. In computing parlance, this is known as the amount of memory a CPU can address.

With a 32-bit chip, you're limited to a maximum of 4 gigabytes. The step up to 64-bit is, in theory, epic. You can access 16 exabytes. If that doesn't mean much to you, try this. It's 16 billion gigabytes. Yeah, really.

iHone 5S

At this point it's critical to note we're talking about system memory or random access memory (RAM), the stuff the CPU uses to store and retrieve data to process everyday tasks such as opening apps or just flicking around your phone speedily. Not, in other words, mass storage for files and programmes. Think sticks of RAM versus a hard drive in a PC.

But potential is one thing – the likelihood of this new 64-bit revolution making a difference in our iPhone 5S (or Galaxy S5 if the rumours are to be believed) is what matters to today's consumer.

Do we need 64-bit right now?

This question is easy to answer: It's a no. Apple's iPhone 5S and its newest tablets, including the iPad Air, are the only 64-bit phones and tablets running ultramobile operating systems. But they only have 1GB of RAM.

However, if you plot the trajectory of Apple's products, the expectation is that 4GB handsets and tablets will pop up either in 2015 or 2016. Strategically for both Apple and the industry at large, that's just around the corner.

What's more, in the Android arena, we're even closer to busting the 4GB barrier. Higher end smartphones like Samsung's Galaxy S4 and HTC One already sport 2GB, while Samsung's Galaxy Note 3 phablet rocks fully 3GB.

Give it a year or so, and Android devices will be bumping up against the 4GB barrier.


But hang on. Isn't the real question not how much memory you can have, but how much you need? Isn't 4GB of RAM enough in a smartphone or tablet for the foreseeable? The most compelling answer to the contrary involves multitasking or running lots of apps at the same time.

There are two things you need to run lots of apps in parallel. CPU power and memory. Depending on your handset and its operating system, different levels of multitasking are available.

But if you've ever pulled up an app you haven't been using for a while but has been supposedly running in the background, only to find it takes an aeon to respond, there's a reason.

It's typically because the app's state has been pushed quietly away from what you;re currently doing, and needs a technological heave to bring it back in front of your eyes – creating the delay. Given sufficient memory, you'd never have to swap an app into mass storage. And that would make your handset more responsive.

The PC parallel

A handy proxy here is the desktop computer or PC and the hardware survey operated by game developer Valve, the outfit most famous for the Half-Life series of first-person adventure shooters.

Valve surveys users of its Steam gaming platform and the latest results show that nearly half of Steam users still have 4GB of RAM or less. On a desktop PC. In 2013. Fully 10 years since the first 64-bit PCs arrived. Uh huh.

What it all boils down to is this: there's no immediate or pressing need for beyond-4GB in a smartphone. In some very limited multi-tasking scenarios with particularly demanding apps it will probably help. But that's about it.

Instead, it's a little further out, in a future where your handset becomes your primary computing device that more memory becomes critical.

This a future where you walk into your office and your handset wirelessly and automatically hooks up to a large desktop display and powers all your demanding productivity, multimedia and even gaming apps.

Desktop PCs

How soon that will happen is hard to say. But we can see the beginnings of this transition in 2-in-1 tablet-laptop devices and the phones that morph into tablets, like of Asus's Padfone family.

Five years from now, smartphones will very likely be powerful enough for all but the most intense gaming and number crunching apps.

If that's the memory addressing part of the problem covered, are there any other benefits to 64-bit computing? Ultimately, that comes down to implementation.

Picking apart the performance gains

The shift to 64-bit offers an opportunity for chip makers to refresh both the instruction sets that define how mobile CPUs operate and their detailed internal architectures. At this point, things can get rather technical.

We could have a discussion about added register space, bigger page sizes and increased width for floating point calculations. Revisions like these are indeed due from ARM with ARMv8, which is a whole new instruction set, albeit backwards ARMv7.

ARM, of course, is the UK company whose mobile CPU instruction sets and processor core designs form the basis of nearly all smartphones and tablets available today. That includes Apple's A7 chip, which is the first ARMv8-based chip in a smartphone or tablet.

Using the A7 as a guide, early benchmarks comparing 32-bit code to 64-bit show some pretty impressive performance boosts. There are also reports of ARM's new 64-bit core design, the Cortex-A57, running as much as 50 per cent faster in 64-bit mode than the current 32-bit Cortex-A15.

Of course, the problem here is that unpicking the performance benefits that derive directly from 64-bit computing from those that come with a generational transition in CPU architecture is very tricky. But there will almost definitely be some.

What about 64-bit Android devices?

So, now we have a rough idea of the likely benefits of a 64-bit chip in a smartphone or tablet might be, when is the rest of the industry going to catch up? Put simply, what about 64-bit Android devices, set to debut in 2014?

When Apple announced the A7, the impression was conspicuously of a competition caught off guard. A senior executive from Qualcomm, maker of the popular Snapdragon chips, quipped that 64-bit was a gimmick, only to have his remarks officially retracted and find himself mysteriously demoted.

Samsung was quick to confirm it was planning 64-bit chips for its own Galaxy handsets and tablets. But since then has emitted rather mixed messages.

The bottom line is that we don't have firm dates for the arrival of 64-bit chips from Qualcomm or phones using the technology from Samsung, but the former has now announced it's first 64-bit chip, the Snapdragon 410, albeit designed for the budget market.


Of course, for any of that to matter we'll need a 64-bit capable version of Android. Oh, and some apps, too. Making Android itself 64-bit capable is pretty straightforward, though.

It's based on the Linux operating system which has itself been 64-bit capable for around a decade, and on top of that Google has recently taken to inserting a tantalising little 64-bit icon when displaying the list of new features coming to Android at press and trade events.

So, 64-bit is clearly on it's way, although it didn't land with KitKat (although whispers are that it might support it. But really, that detail isn't hugely critical. You need both hardware and software and you can be confident that when the first 64-bit phones appear, Android will be ready for them.

Whether the application ecosystem will be is another matter. For apps to fully benefit from the new 64-bit architectures, they'll have to be recompiled. In a lot of cases, that will be a fairly trivial job for developers. But the fact is the jury is out on how quickly that transition will happen as we're still yet to see a definite reason for it.

Should I care about 64-bit then?

If you're wondering about any downsides to 64-bit, well, it's a question of complexity. Inevitably things like code size and DRAM fetches get bigger, and 64-bit programmes simply tend to be larger and so more computationally complex.

The issue here is power efficiency. Any time you increase performance, you'll need to improve performance-per-watt to maintain battery life. So 64-bit isn't really any different to other performance-boosting options. Add mores cores and all things being equal, you use more power.

So, here's the upshot. 64-bit phones and tablets are heading for the mainstream and fast. Apple is already there and some time in 2014, the first 64-bit Android phones will appear. By late 2015, it's likely most or all high end tablets and phones will be 64-bit.

A few years after that, nearly everything will be 64-bit.

And while it may be some time before we truly need the increased memory addressing that comes with 64-bit, the broader performance improvements that go hand in hand with the new chips will be very handy in the near future.

In that context, Apple probably doesn't deserve a kicking for bigging up 64-bit or making the move too early. There's no doubting its 64-bit A7 chip is a powerhouse that delivers awesome performance you can use today.

More to the point, the hardware has to come first and lay the foundations for this brave new world of 64-bit phones and tablets. Build it and the software and apps will surely come. We therefore welcome our new 64-bit overlords. You should, too.

CPU 64-bit iPhone 5S Samsung Galaxy S5 Qualcomm Snapdragon 410 cpwhot cpwhub cpwfeatured cpwcarousel
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