WiFi Performance

While cellular data is often the center of smartphone connectivity, it’s often the case that people rely on WiFi instead of cellular data for the bulk of their data transfers. As a result WiFi is a pretty important part of the overall smartphone experience. In the case of the iPhone 6s, the major change from the iPhone 6 is that rather than single stream 802.11ac, the iPhone 6s now has dual spatial stream 802.11ac. This increases the maximum physical link rate to 867 Mbps. There’s been some confusion over what’s used for the WiFi chipset, and as far as I can tell this is definitely a Broadcom solution, which is identified as BCM4350 in the system judging by the device ID. This chipset is shared with the Macbook, which is probably helpful for driver development. In order to test how well this performs, we use iperf2 in UDP mode to attempt to determine maximum practical bandwidth. It’s worth noting here that the iperf2 ports on iOS are still amazingly buggy though, so these results are no guarantee as far as I can tell.

WiFi Performance - UDP

Interestingly enough, for whatever reason the iPhone 6s holds a minor lead over most of the other devices in this test. I’m not sure what’s causing this, but in practice I found that WiFi on the iPhone 6s worked without any noticeable issues. Reception is noticeably improved when compared to the iPhone 6 due to the addition of a second spatial stream which means that throughput at the same distance is higher.


Accurate location is often critical to a number of popular applications for smartphones like any kind of navigation or mapping application, which is going to be an incredibly painful experience if the GNSS system in the phone has poor sensitivity to the signals used in the various GNSS systems available today. Although I have no hard evidence to go on, given the use of a Qualcomm modem in this phone I strongly suspect that this phone is using Qualcomm's IZat location services. I would normally run some cursory testing here with a GPS test application, but because iOS offers no way to clear assistance data and location services are disabled if there is no prior connection to download assistance data, there's no way to do the usual cold lock testing.

A warm lock in which connection was immediately established to begin downloading assistance data achieved lock within 15 seconds, and in general I've never had issues with location services in the iPhone 6s in my time using it.


Over the course of the review, there are a lot of various bits and pieces that I learn about a phone that might be of interest, but aren’t necessarily examined in intense depth because of either limitations in our testing or the issue of interest isn’t significant enough to examine closely. For example, the fuel gauge appears to be a TI design win as there are references to a BQ27540 chip. The A9 SoC also contains a dedicated AES accelerator for things like full disk encryption and FairPlay DRM. The display backlight appears to use the TI LM3539 driver, but other evidence within the system suggests that this isn’t the only backlight driver for the display.

On the audio side of things, although I haven’t been able to do deep investigations into audio quality it appears in the system that the audio codec used is Cirrus Logic’s CS42L71 which also appears to be responsible for microphone input. However, instead of using an amplified on the audio codec a dedicated amp is used for the speaker, which appears to be a Cirrus Logic CS35L21. Subjectively, the speaker sounds pretty similar to the iPhone 6, but at the high end of the volume range it feels like volume was increased while also increasing distortion. Turning down the volume to a comparable level makes both sound pretty much the same.

More reading of the system files reveals some noticeable codenames like Stockholm which appears to be related to NFC and payments in some way. The fingerprint sensor is referred to as Mesa, and the authentication/secure element appears to be Sand Dollar. The charger chip is referred to either as SN2400 or Tigris. Some sort of accessory detection chip is referred to as TriStar2 or CBTL1610. The ambient light sensor is referred to as CT821 but I can’t find anything on what this is at all.

Display Final Words


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  • Der2 - Monday, November 2, 2015 - link

    Its about time. Reply
  • zeeBomb - Monday, November 2, 2015 - link

    Oh man...oh man it's finally here. I just wanted to say thank you for faithfuflly using all your findings to incorporate this review. It may have take a little longer than expected, but hey, this is my first anandtech review that I probably camped out for it to drop, lol...thanks again Joshua and Brandon! Reply
  • zeeBomb - Monday, November 2, 2015 - link

    Ugh. I meant Ryan Smith...sorry! Waking up at 5 isn't the ideal way to go... Reply
  • Samus - Thursday, November 5, 2015 - link

    That's what she said, Der bra. Reply
  • zeeBomb - Sunday, November 8, 2015 - link

    Very valid point. Speaking of valid points... 500! Reply
  • trivor - Thursday, November 5, 2015 - link

    Have to disagree with your statement that the high end Android phone space has stood still. With this round of phones the Android OEMs have all upped their game to approximate parity with the iPhones and in some cases exceed the performance and quality of images taken by an iPhone. In addition, on phones like the LG G4 the option of having manual control of your picture taking and supporting RAW/JPEG simultaneously is a huge advance for smartphones. Add to that, phase change focusing, laser rangefinder for close focus, generous internal storage (32 GB) and micro SD expansion (which works quite well on Lollipop - not sure about Marshmallow yet) you have a great camera phone. It also has OIS 2.0 (whatever that means) at a significantly lower cost than even the low end (16 GB) iPhone 6s @ $450-500 for the G4 versus $650 for the iPhone. While iOS seems to get apps updated a little quicker, look nicer from what I've heard and seem to be a little more feature rich. Conversely, the Material Design language has greatly improved the state of Android interfaces to give Android OEMs a much more stable OS - although the first builds of Lollipop were not ready for prime time. Also, let's not forget that Android dominates the low - middle range of Smartphones below $400 with near flagship specs, excellent cameras in phones like the Motorola Style (Pure Edition in the US), Motorola Play (is apparently the base model for the Droid Maxx 2 for Verizon, a number of the Asus Zenphones, the Moto G and E. Also, the new Nexus' (6P and 5X) are both competitive across the board with new cameras with 1.55 micron pixels that let in significantly more light than the 1.12 pixels in other cameras, are competitively priced (especially the 6P @ $499), and are overall very nice handsets. Finally, the customizability and wide variety of handsets at EVERY PRICE POINT make Android a compelling choice for many consumers. Reply
  • Fidelator - Friday, November 6, 2015 - link

    I couldn't agree more, the Android space has not stayed still, if anything, most of the problems on that side were due to Qualcomm's lack of a good offering this year, still, the phones were further refines in other areas, saying this is overall the best camera phone given the only advantage it has over the competition is reduced motion blur is complete bull, the UI is far from the best given that auto on both the SGS6/Note 5 and the G4 is as effective yet those still offer great manual settings.

    The -barely over 720p- display on the 6S is inexcusable for 2015 and given the starting price of the 6S should not be passed as an acceptable not even as a good display.

    Where Apple deserves credit is with the A9, it is miles ahead of anything the competition currently offers, they have made some fantastic design choices, it just is on the next level.
  • robertthekillertire - Monday, November 9, 2015 - link

    I'm actually very happy with Apple's decision to stick with a lower-resolution screen. Which would you rather: a smartphone with an insanely high pixel count that your eyes probably can't appreciate anyway, or a smartphone with a lower PPI (but barely perceptibly so) that gets better battery life and has smoother UI and game performance because it's not trying to push an absurd number of pixels at any given moment? The tradeoff just doesn't seem worth it to me. Reply
  • MathieuLF - Tuesday, November 10, 2015 - link

    But your eyes can tell the difference... When I had my iPhone 6+ and Nexus 6P side by side I can see it right away that the Nexus has more pixels Reply
  • Cantona7 - Tuesday, December 1, 2015 - link

    But the difference is not large enough to justify heavier power consumption and greater graphics requirement. I agree that more pixels is certainly more pleasant to the eyes, but I'd rather greater battery life. If the Nexus 6P had a lower resolution screen, it would have a even greater battery life which would be awesome Reply

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