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.