Processor
iPhone 6: Apple A8 20nm, 20 per cent faster CPU, 50 per cent faster GPU
iPhone 5S: Apple A7 dual-core 1.3GHz, 64-bit, 1GB RAM
Both the device come with a new generation 64-bit Apple A8 chip, which is 13 percent smaller and up to 25 percent faster than the previous-generation A7.
Apple claims the Apple A8 provides 20 per cent more CPU power and 50 per cent more GPU power.
To make the new CPU more efficient, Apple has changed the system architecture from 28nm to 20nm – meaning it uses absolutely tiny transistors. This also means it's able to run cooler.
Battery Life
iPhone 6: 11 hours browsing, 11 hours video
iPhone 5S: 10 hours browsing, 10 hours video
For iPhone 6 the company claims to offer around 11 hours of continuous video playback and 14 hours of 3G talk time.
As we expected, Apple has chosen to make the iPhone 6 slimmer rather than significantly adding to the battery life.
The iPhone 5s, meanwhile, is rated for up to 10 hours of video playback and 10 hours of 3G talk time, but it lasted 14 hours and 31 minutes in our own continuous video playback testing.
On the battery front, it is still good, but that great.