Both Samsung and TSMC are making A9 chips for the iPhone 6s. Here's how to check which one your device has.
Step One:
Install Lirum Device Info Lite from the App Store for free.
Step Two
Launch the app and look at the Model number under the Home tab.
If you have model N66AP (6s Plus) or model N71AP (6s) then you have the Samsung chip. If you have model N66MAP (6s Plus) or N71MAP (6s) then you have the TSMC chip.
Step One:
Install Lirum Device Info Lite from the App Store for free.
Step Two
Launch the app and look at the Model number under the Home tab.
If you have model N66AP (6s Plus) or model N71AP (6s) then you have the Samsung chip. If you have model N66MAP (6s Plus) or N71MAP (6s) then you have the TSMC chip.