Much hullabaloo has been made of late over Apple's dual-sourced A9 SoCs. Some enterprising YouTubers fueled a panic when they demonstrated considerable differences in battery life between Samsung- and TSMC-powered iPhone 6S handsets under certain conditions. Consumer Reports has gone in-depth to put those findings to the test, and the company found that there isn't any reason to worry over which foundry's A9 is in your shiny new iPhone.
To measure the phones' battery life, Consumer Reports carried out two different tests on two iPhones: one with a TSMC A9, the other with a Samsung chip. One test simulated web browsing on Wi-Fi. Each phone was set to play music in the background at the same time. The phones ran this load until one of them ran out of juice. The battery life results from this test differed by less than one percent, according to CR.
Consumer Reports also tested its iPhones' run times while the devices were connected to a cellular network. The company ensured consistency in this test by connecting the phones to its own base station emulator inside a custom-built radio frequency isolation chamber. Once again, the difference was tiny: CR said the results from this test differed by less than two percent. In both tests, the phones reached a similar surface temperature of around 84 degrees Fahrenheit, which CR logged with thermocouples on the devices' bodies.
These test results come with one caveat: the sample size is tiny. Even so, the company's devotion to controlling environmental variables is admirable. The testers used two phones from the same carrier. All of the system and app settings were configured identically, and the screen brightnesses were set to the same value with an illumination meter. Plus, you know, the company has its own RF isolation chamber and base station emulator. That's some serious benchmarking equipment.
CR's results mirror the anecdotal experience of two TR contributors whose iPhone 6S Pluses have A9s from both sources. This data also lines up with Apple's official statement to TechCrunch when the controversy first surfaced. Now that we have some independent testing and verification of Apple's statements in a controlled environment, perhaps iPhone 6S owners and prospective buyers can rest easier.