The iPhone 5S is a significant step up in terms of power and performance over the iPhone 5. The new A7 dual-core 1.3GHz processor with 1GB of RAM sounds feeble when compared to the quad-core 1.9GHz 2GB RAM of the Galaxy S4 or stonking 2.2GHz of the Sony Xperia Z1. But phones are not top trumps and the processor on the iPhone 5S is hugely impressive, even though it looks much weaker on paper.
Apps load instantaneously and 3D games looks jaw-droppingly good. The cars in Real Racing 3 look almost photorealistic while Infinity Blade 3 provides console quality graphics.
The benchmarks support the experience. Only the Snapdragon 800 processor on the Xperia Z1 outperforms the iPhone 5S. In our CPU, browsing and graphics tests the 5S scored 40% faster than the Galaxy S4 and more than 100% faster than the iPhone 5, the phone it replaces.
It's impressive and just goes to show that picking the right phone is not about looking at the numbers anymore, just like picking a camera that takes great pictures isn't about how many megapixels it's packing.
For a full breakdown of tests and results you can view our iPhone 5S benchmarks at the end of this review.
The first 64-bit phone processor
But before you do it's worth taking the time to think about the 'world first' Apple claimed in making the A7 chip the first 64-bit mobile processor. The transition to 64-bit computing on the PC took a long time. A fragmented system ensured it was years before the benefits were felt in the home, and those who jumped to 64-bit early found that all the software they wanted to use wasn't ready yet.
Fast-forward a few years and 64-bits on the PC has become the norm and Apple has added the A7 SoC (system on chip) processor to the iPhone 5S, making it the first 64-bit phone.
While the debate about its benefits right now is fearsome, it does have some small benefits (emphasis on the small) that will no doubt grow in future. The encryption side of the Touch ID is the most obvious benefactor, though arguably games will begin to benefit once developers start to unlock the full potential of the A7 chip.
But it's really a move for the future that means that developers can get busy supporting 64-bit now when it's less critical so that its true potential can be unlocked on future iPhones and iPads. If you want to find out more about the iPhone 5S processor and 64-bit computing then read our guide: What is 64-bit? The Apple A7 chip explained.
The M7 processor
Of greater import to the here and now is the new, much less powerful 'co-processor' chip called the M7. The purpose of the M7 is to deal with all the motion capture data provided by the accelerometer, gyroscope, and compass. This data requires much less processing power to manage, which means using the main processor is overkill and seriously inefficient.
So the M7 helps lighten the load on the battery, but it also has one more important power saving trick up its sleeve.
If you leave the iPhone 5S in a location where there's no signal, a gym locker for example, the M7 will recognise that the phone has not been moved and that there is no signal in the area. Pinging the networks constantly to find signal is one of the biggest battery drains on a phone and there's no point doing it if there's no signal to be found.
This particular feature only works when the phone is immobile, but it's not the only benefit of the M7. For example, It allows to the iPhone 5S to know when you switch from a car or walking, switching the directions to suit, but it could also open a whole new set of possibilities for third-party accessories to use its specialist processing. The likes of the Nike Fuelband, Fitbit Flex and similar gadgets seem the most likely benefactors, but we'll have to wait and see how they use it.
iPhone 5S – Battery Life
One of the few issues the iPhone 5 had was a limited battery life. In this area the Samsung Galaxy S4 trounced it. Apple has tried a few things to improve battery life on the iPhone 5S, like including the M7 processor, but to varying degrees of success.
The most obvious resolution would be a bigger battery. This poses a problem for Apple as the iPhone 5S shares the same chassis as the 5, so there's not a lot of additional space to play with. Regardless it has managed to increase the size from 1440mAh to 1560mAh, about 8%.
Together with the touted iOS 7 efficiency improvements and processor efficiencies we did notice that the iPhone 5S outlasts the iPhone 5.
We got between nine and 10 hours of mixed usage, including streaming video, gaming, browsing, calls, taking pictures and video and listening to music.
Impressively steaming, 720p video at half screen brightness seemed to tax the battery very little, with only 3% disappearing in half an hour. Playing music stored locally using the included Earpods at high volume saw of a 4% drop in 30 mins. Gaming, particularly intensive 3D games such as Real Racing 3 and Infinity Blade 3, sapped juice at a steady, but reasonable, rate while 3G browsing was the other main drain.
Used normally we managed to make the battery last for a day and a half before requiring a charge, better than the iPhone 5.
Unfortunately the iPhone 5S is still not on a par with the Android big boys. The Samsung Galaxy S4 outlasts it by some margin and the removable cover offers the ability to switch batteries if you're really desperate and very well organised.
On the other hand the iPhone 5S is much smaller and lighter, allowing the option of adding a power-pack case without it becoming too cumbersome. These can be pricy though and ruin the sleek design somewhat.
So, while it's an improvement on the iPhone 4/4S/5 in this regard, it does feel as if Apple has chosen to ignore serious improvements in this area. It's 'good enough' for the large majority, but if there's an area it cedes noticeable ground to the competition, it's here.