The larger screens that came with the iPhone 6 and 6 Plus were the biggest hardware changes the iconic brand has yet seen and represented a major philosophical shift for Apple. Competitive pressure from Android OEMs and more cognizant consumers shattered Cupertino's stranglehold on what a smartphone should look like. Its customers wanted larger screens, and Apple gave them what they wanted.
This is an "s" update, however, so there's no radical redesign or reimagining of the iPhone. Instead, Apple focuses on boosting performance and refining last year's design for the iPhone 6s and 6s Plus. While their screens are the same size and resolution, most of the internals are new, starting with the A9 SoC. Apple's custom-designed, dual-core 64-bit CPU gets more cache and higher IPC (instructions per cycle). The A9 also gets a new PowerVR GPU, with its own architectural enhancements and two additional cores. Using a new FinFET manufacturing process allows Apple to ramp up clock frequencies, further increasing performance—up to 70 percent for the CPU and up to 90 percent for the GPU, according to Apple.
The M9 motion coprocessor is no longer a separate chip. It now resides on a special low-power island within the A9 SoC. This change unshackles Siri from the power outlet, an inconvenient restriction placed on the iPhone 6, whose M8 coprocessor took up additional space on the motherboard and drew too much power to be left on, listening for voice commands, when running on battery power. Now Apple's digital assistant is always listening, ready to respond as soon it hears you say, "Hey Siri." The M9 still collects data from the accelerometer, compass, gyroscope, and barometer too, feeding it to fitness tracking apps that log steps taken, distance traveled, and elevation traversed. Additionally, it now measures the speed of movement.
Memory capacity is only one area where the iPhone is falling behind, though. When it comes to camera performance, Samsung's Galaxy S6 devices surpass the iPhone 6 and 6 Plus. Apple hopes to rectify this situation by giving the 6s and 6s Plus new front and rear cameras that offer higher resolution and the ability to record 4K UHD videos. We'll discover if these changes push the iPhone back into the lead in performance and features once again later in the review.
The new iPhones should now be on par with the Wi-Fi performance of other flagships. Last year, the iPhone 6 added support for 802.11ac Wi-Fi, boosting theoretical bandwidth from 150Mb/s on the iPhone 5s to 433Mb/s using a single spatial stream and an 80MHz channel. For the 6s, Apple adds a second spatial stream, elevating bandwidth to a maximum of 867Mb/s.
Unfortunately, when it comes to the base storage option, the iPhone is still stuck in the past, offering a meager 16GB (~12GB usable). This is not enough for a modern smartphone, let alone a flagship phone. My mother-in-law, who has not installed any apps and does not do much more than text, managed to completely fill her 16GB iPhone 6 Plus with just pictures and a few short videos. With a larger camera sensor and the ability to shoot 4K video, the new iPhones will consume even more storage space. Apple does offer 64GB and 128GB storage options, but they do not come cheap.
Apple iPhone 6s Specifications
Apple iPhone 6s Plus Specifications
The iPhone "s" models are not just about new silicon, however. It's become a tradition for Apple to introduce a new usability feature in lieu of a new design. The iPhone 4s introduced Siri, Apple's voice activated assistant; the 5s added Touch ID, a functional fingerprint scanner; and now the 6s squeezes in 3D Touch, a pressure sensitive display with haptic feedback. Adding a third control dimension to the now familiar two-dimensional multi-touch controls allows for two new interactions: Peek and Pop. Will these become as ingrained as pinch-to-zoom, or should they be relabeled Try and Forget? We'll explore 3D Touch more in a bit.
The iPhone 6s and 6s Plus are packed with more cellular silicon than any phone we've ever seen. There are multiple power amplifiers, front-end modules, and antenna switches from Avago, Murata, Qorvo, RF Micro Devices, Skyworks, and TriQuint, with some of these components specific to certain iPhone model numbers, depending on regional frequency requirements.
All of these chips surround a Qualcomm MDM9635M baseband processor. Manufactured on a 20nm process, it supports Category 6 LTE speeds of up to 300 Mbps on the downlink (2x20 MHz carrier aggregation with 64-QAM) and up to 50 Mbps on the uplink (1x20 MHz with 16-QAM). It also supports all major radio modes, including GSM/EDGE, UMTS (WCDMA, TD-SCDMA), LTE (LTE-FDD, LTE-TDD) and CDMA2000. This new processor consumes less power than the 28nm MDM9625M in the iPhone 6, while delivering higher downlink speeds than the older Category 4 LTE (150 Mbps) part.
The RF transceiver is another Qualcomm part. The WTR3925 is the first single-chip solution from Qualcomm to support all of the 3GPP approved carrier aggregation band combinations, eliminating the need for a second receive-only transceiver like the iPhone 6 used. Qualcomm's QFE1100 envelope tracker, part of the company's RF360 suite, dynamically adjusts voltage to the power amplifiers, wasting less energy and reducing heat generation.
All of this is required for supporting up to 23 LTE bands, up from 20 in the iPhone 6 and 13 in the 5s, the most in any smartphone, assuring the iPhone 6s will work in nearly any country you might travel to. Here's the full list of supported frequencies.
Voice over LTE (VoLTE) and Wi-Fi calling, which allows you to make higher‑quality wideband calls over a Wi‑Fi connection, were both supported on the iPhone 6 and carry over to the 6s. This latter feature came with an unfortunate limitation on the 6, however: turning it on would break Apple's Continuity feature. The iPhone 6s eliminates this restriction, allowing both features to be enabled without interfering with each other.