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There are so many new smartphones and tablets released onto the market, and each one makes a claim about how it is faster, more powerful and has better battery life than its rivals.
Much of the attention falls on the processor, throwing ever larger numbers of cores and gigahertz and bits at you to show off its prowess.
But do you really know what it all means? In this guide, we’ll cut through the jargon to explain what you need to know about smartphone processors.
Introducing The System On A Chip (SoC)
When talking about mobile processors, we first need to be clear about what exactly we mean by “processor”.
In desktop PC and laptop specifications, the term processor tends to refer specifically to the CPU, the central processing unit, the element that provides the brainpower to the computer.
In mobile terms, “processor” more often refers to the System on a Chip (SoC).
The SoC is a single chip about the same size as a desktop CPU that contains most of the key components required to make a device function.
These include the CPU, as well as the GPU (the graphics processing unit, which would normally be found on a separate graphics card in a PC), and various radios and sensors for things like Wi-Fi, Bluetooth, GPS and even cellular data.
The SoC also determines specific features that a device can support, such as the resolution of images the camera can capture, or whether 4K video can be recorded or played.
The main benefits to an SoC are its size, its lower power consumption and lower heat emissions.
Reading Processor Specs
So how do you read the processor specs for a device? The iPhone 6 specifications include:
- Apple A8
- Dual-core 1.4GHz Cyclone, 64-bit, ARM v8-based
- PowerVR GX6450
This tells us that the SoC is Apple’s A8, which the company designed. The CPU is dual-core (which means there are two processing units), clocked at 1.4GHz. Cyclone is Apple’s name for the CPU.
The CPU is also 64-bit and based on the ARM v8 architecture. The GPU is based on the PowerVR GX6450 from Imagination.
The specs for the HTC One M8 include:
- Qualcomm Snapdragon 801
- Quad-core 2.3GHz, 32-bit
- Krait 400
- Adreno 330
Here, HTC is using a Snapdragon SoC from Qualcomm. 801 is the name of the model – as of early 2015 the 810 was the flagship model in the range.
The CPU is quad-core, clocked at 2.3GHz. With twice as many cores, and more than 50% extra clock speed the CPU appears to be significantly more powerful than that on the iPhone 6, however as we’ll see that isn’t necessarily the case.
Krait 400 is the name of the CPU, and is also based on the ARM architecture. Graphics is powered by the Adreno 330 GPU, which is part of the Snapdragon SoC.
In both of these examples, the CPUs are based on ARM architecture.
This is created by ARM Holdings and includes an instruction set that controls how the CPU works. This is licensed to the various SoC manufacturers who incorporate it into their products.
ARM has dominated the mobile space for many years, largely thanks to the lower power consumption of its processors (and improved battery life) when compared to the opposition. Intel has been attempting to make inroads into the markets in recent years with the x86 that is popular on the desktop, but with limited success.
There’s little consumer benefit in trying to understand the details of the ARM architecture, other than knowing that the latest version is better (i.e. faster and more power efficient) than the last one. For instance, the ARM v8 as used in Apple’s A8 is 64-bit, unlike the v7 used in the HTC One.
Cores versus Clock Speed
What does have a consumer benefit are the cores and clock speeds of a processor. Most users hone in on these numbers for one simple reason: bigger numbers look better than smaller numbers.
It’s not quite that simple, though.
The clock speed measures, in gigahertz, the speed at which a CPU is able to process instructions. All things being equal, a 2.5GHz processor will be faster than a 2.0GHz processor.
But things are rarely equal. A newer version of a processor is likely to be faster than an older one, even at slower speeds; a CPU based on a newer architecture is likely to be faster; and the number of cores also makes a difference.
A core is a processing unit within a CPU. Each one can handle tasks independently, or can be combined to provide more power to particularly intensive tasks.
In normal use, a multi-core processor will see the cores share the workload of the OS and all your running apps without ever reaching their maximum clock speed. The result is a snappier, more responsive device, with better multitasking support, plus lower heat emissions and less power consumption.
Yet that doesn’t mean Samsung’s octa-core Exynos processor is automatically twice as good as a quad-core Snapdragon, or four times as good as Apple’s A8.
There are so many technical factors that affect the speed and performance of a processor beyond the number of cores and clock speed.
Plus, software needs to be designed to support multi-cores, which isn’t really happening at the moment with eight cores.
And then there’s the impact of device optimisation. Because Apple makes both the processor and the operating system in the iPhone, it is able to optimise both to such an extent that an apparently underpowered dual-core CPU can match or surpass the performance of even the most highly specced (on paper, at least) Android smartphone.
And finally, there’s the fact that even disregarding all of the above, you’d still be really hard-pressed to find enough smartphone apps that need the power of eight processing units running simultaneously. Even PCs and laptops still tend to draw the line at quad-core processors.
In short, sometimes bigger numbers on the spec sheet mean better performance. But, just as often, they don’t.
32-bit versus 64-bit
Another argument over numbers revolves around the choice of a 32-bit or 64-bit processor.
A 64-bit smartphone was first seen with the iPhone 5s in 2013. Android was lagging behind, partly due to the lack of available 64-bit processors and partly due to the fact that Android wasn’t even ready for 64-bit processors until the launch of Lollipop at the end of 2014.
64-bit matters not so much because it’s faster, but because it enables a device to do more.
People often refer to how 64-bit processors enable apps to access more than 4GB of RAM, and while this is true, it’s likely to be a couple more generations before this even becomes an issue.
64-bit is frequently described as “desktop class”, and this is the key. The 64-bit era will see the boundaries between smartphone, tablet and desktop computing blurring even more than they currently are.
The main speed boost to 64-bit processors comes from the fact that the new ARM v8 architecture, which is 64-bit, is considerably faster than the old ARM v7, which wasn’t. Therefore, a flagship device with a 64-bit processor will likely be faster, even if it’s not directly because of the 64-bit support itself.
As it stands, though, a 64-bit smartphone is by no means a must-have just yet.
The Role of the GPU
The GPU is less important on the spec sheet, since the GPU is usually tied to the SoC. So, if a manufacturer uses the Snapdragon 805, it will get the Adreno 420 GPU as part of the package.
Because the GPU affects the visual parts of the user experience, it does have quite an impact on the perceived speed of a phone or tablet, with its interface packed with animations and other visual flourishes.
It’s normally true, however, that low-end, mid-range or high-end device will come with graphics performance to match.
These are the core elements of mobile processors. When reading a specifications sheet, you’ll also be faced with numerous processor brands, each with their own characteristics.
Let’s take a look at some of the most popular ones.
Apple designs the processors for the iPhone and iPad. Because they also design the operating system, the company is able to optimise both parts for maximum efficiency.
- The Apple A8 powers the iPhone 6. It is 64-bit and based on the ARM v8 architecture
- Apple states it has 25% better CPU performance and 50% better graphics performance over the A7 chip in the iPhone 5s
- The iPhone 6 model is dual-core, clocked at 1.4GHz
- The A8X in the iPad Air 2 is 1.5GHz and has three cores
The Snapdragon range from Qualcomm has four distinct tiers. The 200 range is for entry-level devices, the 400 mass-market affordable models like the Moto G, the 600 for mid-range phones and the 800 for flagship devices.
- The flagship Snapdragon 810 is powered by an octa-core, 64-bit CPU
- Comes with Adreno graphics
- The 810 includes a built-in Shazam app for music recognition
- Snapdragon chips are used on devices such as the HTC One range, the Moto X and the Samsung Galaxy Note 4
The Exynos SoC is built by Samsung for use in its own range of Android smartphones and tablets.
- ARM-based, and the first quad-core SoC for smartphones launched with the Galaxy SIII in 2013
- Current versions are 64-bit and octa-core
- Performance in benchmarks shows a high-end Exynos to be comparable to a high end Snapdragon
- Samsung often limits Exynos use to specific markets, with Snapdragon’s used in others
There are many other processors in smartphones, at varying levels of price and performance. They include:
- NVIDIA K1: ARM-based chip seen in the NVIDIA Shield and Nexus 9 tablets. Uses 4+1 cores, which means four cores for normal use and one low-power core for use on standby. Graphics performance is ahead of many comparable SoCs in benchmark tests. The newly announced X1 promises double the speed.
- Mediatek: Low cost processors often used in entry level devices by smaller brand manufacturers. Good paper specs, not always matched by performance in benchmark tests.
- Intel Atom: Used in a small number of smartphones and tablets, such as the Asus ZenFone and Nokia N1. Based on the x86 architecture. The Intel Atom SoC for mobile devices is not the same as the Atom CPU for laptops and netbooks. Processors based on the x86 architecture do not have 100% compatibility with software built for ARM-based processors.
There’s a lot to take in when trying to figure out which smartphone will give you the best performance.
Understanding some of the jargon involved in processor specs is a good place to start, but as we’ve seen, it’s not always the case that bigger numbers will equate to better performance in the real world.
You can view benchmark tests to see a device’s speed in lab conditions, but it’s important to remember that the processor is just one factor among many that affect the performance of a phone.
Which smartphones specs are most important to you? Do you always check out benchmark tests before you buy, or do you think things like design and build quality are more important?
Image Credits: NVIDIA X1 via nvidia.co.uk, Snapdragon 810 via Qualcomm, Apple A8 via ifixit.com, HTC One M8 teardown via ifixit.com, Galaxy Note 4 via samsungmobilepress.com, iPhone 6 via apple.com, Nokia N1 insides via nokia.com