Shortly after the launch of the Apple iPhone 6S and 6S Plus it was discovered that Apple was dual-sourcing the A9 processor, probably due to the sheer amount of processors required to meet expected demand. Apple was using TSCM to provide A9 chips, built on its 16nm process, and Samsung to produce A9 chips using its 14nm process. According to MacRumours the distribution of TSMC and Samsung chips among the new Apple smartphones is approximately 50:50.
Initial investigations suggested that both makes of A9 chip performed pretty similarly with no significant differences in the speeds of operations when the chips are tasked. However news has been emerging that the choice of A9 chip can have a significant impact on the battery life offered by your shiny new Apple iPhone 6S or 6S Plus. With the non-user changeable battery favoured by Apple, having a decent battery life using the supplied built-in battery is pretty important. People are spending up to £789 on these pocket gadgets.
In a battery life test comparing the TSMC and Samsung A9 chip powered Apple iPhone 6s Plus variants the results below were shared by a Reddit poster. MacRumours notes similar other independent findings via its own forums and the Chinese MyDrivers site. Users also found that the Samsung chip ran noticeably hotter – suggesting wasted energy.
It must be remembered that benchmarks don't always translate to real-world performance and this is also true with battery stress test benchmarks. There could also be other variables influencing the small number of test results so far published. However some people are already deciding to return Apple iPhone 6S models with Samsung A9 chips if they are within the no quibble returns time window (varies between markets).
For those interested in determining their Apple iPhone 6S CPU maker there is a tool available to help you find out. CPUIdentifier is available here and, as unsigned code, is to be installed at your own risk.
UPDATE: Apple has uncharacteristically made a statement about the above issues, it talks down any difference between the TSMC and Samsung made A9 processors:
"With the Apple-designed A9 chip in your iPhone 6s or iPhone 6s Plus, you are getting the most advanced smartphone chip in the world. Every chip we ship meets Apple's highest standards for providing incredible performance and deliver great battery life, regardless of iPhone 6s capacity, color, or model.
Certain manufactured lab tests which run the processors with a continuous heavy workload until the battery depletes are not representative of real-world usage, since they spend an unrealistic amount of time at the highest CPU performance state. It's a misleading way to measure real-world battery life. Our testing and customer data show the actual battery life of the iPhone 6s and iPhone 6s Plus, even taking into account variable component differences, vary within just 2-3% of each other."