Apple says difference in the battery life of TSMC and Samsung made A9 chips is only 2% to 3%
Apple says that the 2%-3% difference is within the tolerance that is acceptable between two iPhone models, even if they had chips made by the same manufacturer. Which means that if the guy next to you is holding the same exact iPhone you own, and says that his battery life is running 3% longer than yours is, you have no complaint with Apple.
However, a Geekbench battery test revealed that an Apple iPhone 6s powered by the TSMC version of the A9 would provide 1 hour and 5 minutes more battery life than the same model containing Samsung's version of the chip. In addition, the TSMC powered iPhone 6s produced a slightly higher AnTuTu score than an iPhone 6s powered by Sammy's A9. After the two phones went through the AnTuTu test the same number of times, the Samsung powered unit had less battery life remaining (71%) than the iPhone 6s with the TSMC chip inside (77%). That 6 percentage point difference is more than double the 3% variance that would be acceptable to Apple.
Of course, you can't truly go with benchmark tests to determine if one A9 chip offers a longer battery life than another. Real world results would probably be different, and could fit within Apple's acceptable tolerance range. By the way, earlier today we showed you a way to discover if you have a TSMC or Samsung made A9 chipset powering your Apple iPhone 6s, or Apple iPhone 6s Plus. No matter which chip you have in your new iPhone, Apple says that you are getting the same experience as others toting your model. After all, a 3% difference on a phone running 6 hours would be an extra 11 minutes, which is not enough extra battery life to lose sleep about.
source: MacRumors, TechCrunch