Apple has sourced A9 processors found in the iPhone 6s and iPhone 6s Plus from two different suppliers, both Samsung and TSMC. While the design and real-world performance are practically the same, each chip manufacturer is actually using a different die size. The Samsung version (APL0898) is arguably more advanced since it uses a 14-nanometer process, resulting in an A9 with a footprint of 3.78 square inches. By contrast, the TSMC chip (APL1022) takes up 4.11 square inches thanks to a 16-nanometer process. So why does any of this matter?
In some cases, intrepid iPhone 6s analysts have shown TSMC chips running cooler and providing improved battery life over the Samsung version. Much of the controversy over the alleged "chipgate" was based on artificial benchmark scores, such as Geekbench showing performance differences in the two die sizes. However, later testing based on real-life usage has shown any difference in battery life or performance to be negligible.
Even though the differences between each supplier's A9 system-on-chip (SoC) is practically nonexistent to the typical user, some iPhone 6s owners will want to know which processor they have. In that case, here are instructions for viewing the supplier of your A9 chip (OS X required):
1. Register your Apple ID as a developer at http://developer.apple.com/programs/enroll/2. Install the latest version of Xcode directly from Apple
3. Run Xcode and navigate to Source Control -> Check Out
4. Enter this URL into the repository location field: https://github.com/WDUK/A9ChipSource.git
5. Connect the iPhone 6s or iPhone 6s Plus to the computer with a USB cable
6. Select your iPhone from the device selection menu in Xcode
7. Xcode will process some files. Wait for the status to indicate Ready
8. To install the A9ChipSource app on the iOS 9 home screen click the Play button
Once installed, simply tap the A9ChipSource icon to run the app on your iPhone 6s or iPhone 6s Plus. The app will open and display the SoC manufacturer immediately.