"Hey Siri" support and possibly wireless charging case alongside AirPower charging mat.
A9 Chip Manufacturing Split 60/40 Between TSMC and Samsung, Not Segmented by Device Size
There was early some speculation that the chips were divided by model, with the iPhone 6s getting the smaller Samsung chip and the iPhone 6s Plus receiving the larger TSMC chip, but new data collected by an iOS developer suggests that is not the case.
Hiraku Wang has created an app that's able to determine whether an iPhone has a TSMC chip or a Samsung chip, and has shared some data on results gathered from users who have installed his app.
According to results from approximately 2,500 iPhones, there are more TSMC chips than Samsung chips. TSMC chips were found to be installed on 58.96 percent of devices, compared to 41.04 percent for Samsung chips.
The iPhone 6s Plus appears to have relatively equal split of Samsung and TSMC chips, with slightly more Samsung chips. Of 1,329 iPhone 6 Plus devices, 56.81 percent have the Samsung chip while 43.19 percent have the TSMC chip.
With the iPhone 6s, the numbers skew heavily towards the TSMC chip. Of 1,086 devices, 78.27 percent have the TSMC chip while 21.73 percent have the Samsung chip.
At this point in time, there is no evidence that the two chips perform differently, as more extensive testing must be done to determine any performance discrepancies. Though the chips are two different sizes, it's highly unlikely there are going to be performance differences large enough to be noticeable during daily usage.
It is possible for users to check which chip version is installed in their iPhones using Wang's utility, but users should be cautious about installing an app via enterprise certificate from an untrusted developer. We do not recommend MacRumors readers install the app.