The iPhone XS & XS Max Review: Unveiling the Silicon Secrets
by Andrei Frumusanu on October 5, 2018 8:00 AM EST- Posted in
- Mobile
- Apple
- Smartphones
- iPhone XS
- iPhone XS Max
Battery Life
The iPhone XS comes with a 2658mAh/10.13Wh battery, while the XS Max has a capacity of 3174mAh/12.08Wh. Again, it’s to be noted that although both phones are quite large form-factor devices by now, Apple’s battery density still largely lags behind the competition. While yes, it’s true that the XS Max’ battery is the biggest that Apple has ever used, it still pales in comparison to the 3500 to 4000mAh that other vendors now employ in the same form-factor.
As we saw in the SPEC analysis, the one advantage that Apple has is an enormous lead in terms of power efficiency of its SoC, which largely makes up for any gap in the battery capacity deficit.
Our web browsing test is a mixed-to-heavy workload that iterates through a set of popular webpages that are hosted on our server. The test loads a web page, pauses, scrolls through it, pauses, and then continues to the next in the set, repeating all over when done. Brightness is fixed at 200cd/m².
The iPhone XS saw a very slight degradation compared to the iPhone X in our test. The 19 minute deficit isn’t terrible, but it does come at a surprise given that Apple had promised improved battery life for the new model. What’s happening is that likely our test is a tad heavier in its workload than what Apple and many other vendors internally test to advertise as the daily battery life of their devices.
The iPhone XS Max came in at 10.3h. Again while this is still good, it’s a degradation over the 11.83h of the iPhone 8 Plus. Here it’s easier to rationalise the difference; the OLED screen of the XS Max is just more power hungry and also has a larger area than the iPhone 8 Plus. Here the increased battery capacity isn’t enough to counteract the panel’s increased needs.
As to why the iPhone XS saw a degradation over the X, I’m not too sure. I did rerun the test on the iPhone X to make sure iOS12 hadn’t impacted the devices – and I got a runtime just 10 minutes lower than what I had tested on the iPhone X back around in January, so the iOS upgrade certainly doesn’t seem to have affected the battery life.
It should be relatively safe to assume that the new A12 should be more efficient in its workloads, even with the increased performance that it brings. One thing that we can’t really verify is the power efficiency at intermediate performance states, as that’s also where CPUs perform a lot of their work at.
We also have to keep in mind the connectivity factor: the new iPhone’s seems to sport a new Broadcom BCM4377 WiFi combo chip which we don’t know much about. Most importantly the new XS have also switched over from a Qualcomm baseband (in our test unit of the iPhone X) to a new Intel XMM7560 baseband.
I’ve generally given up on LTE testing after a few years ago I had run into some serious issues regarding a misconfiguration of my mobile carriers’ baseband stations as they did not have CDRX enabled. This caused an almost 20-30% battery life degradation on Huawei’s devices – and if I hadn’t debugged the issue with HiSilicon I’d probably be none the wiser. Fact is, cellular battery life testing is a lot harder than one would think, and without having a controlled environment, I’m very hesitant to resume cellular battery life testing.
That being said, I will revisit the iPhone X vs iPhone XS battery life topic while on LTE over the weekend and post an update to the review.
Overall, the battery life of the iPhone XS and XS Max are good – they don’t quite reach Apple’s claimed improvements, but that also just might be something that will vary from use-case to use-case.
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Speedfriend - Monday, October 8, 2018 - link
So you would expect them to use that powerful SOC to deliver real battery improvements, but somehow they can't. No one I speak to complains that their modern smartphone is slow, but everyone complains about battery life.melgross - Saturday, October 6, 2018 - link
It’s both. The deep dive isolates the SoC to a great extent. It can be done with any phone.eastcoast_pete - Friday, October 5, 2018 - link
Andrei, thanks for the review! Yes, these are outstanding phones at outrageous prices. I appreciate the in-depth testing and detailed background, especially on the A12's CPU and GPU. While I don't own an iPhone and don't like iOS, I also believe that, phone-wise, the XS and XS Max are the new kings of the hill. The A12's performance is certainly in PC laptop class, and I wonder if (or how) the recent Apple-Qualcomm spat that kept QC's modem tech out of the new iPhones has helped Intel to keep its status as CPU provider for Apple's laptops, at least for now.One final comment, and one question: Andrei, I agree with you 100% that Apple missed an opportunity when they decided on a rather middling battery capacity for the XS Max. If I buy a big phone, I expect a big battery. Give the XS Max a 5000 mAh or larger battery, and it really is "the Max", at least among iPhones. At that size, a few mm additional thickness are not as important as run time. Maybe Apple kept that upgrade for its mid-cycle refresh next year - look, bigger batteries.
@Andrei. I remember reading somewhere that the iPhone X and 8 used 128 bit wide memory buses. Questions: Is that the case here, and how does the memory system and bus compare to Android phones? And, in your estimate, how much of the A12's speed advantages are due to Apple's memory speeds and bus width ?
dudedud - Friday, October 5, 2018 - link
I was sure that only the A$X were 128bit, but i would also want to know if this had changed.RSAUser - Saturday, October 6, 2018 - link
A12 is definitely not in the laptop class unless you're looking at the extreme low power usage tier.Just because it is quite a but faster than the equivalent on mobile does Not mean it can compete at a different power envelope. If that were true, Intel would already have dominated the SoC market. It requires a completely different CPU design. It's wwhy they can use it for the touchbar on the macbook but not as a main processor.
ws3 - Sunday, October 7, 2018 - link
This review did not compare the A12 with “mobile” Intel chips but rather with server chips. The A12 is on par with Skylake server CPUs on a single threaded basis. Let that sink in.As to why Intel doesn’t dominate the SoC space, Intel’s designs haven’t been energy efficient enougj and also the x86 instruction set offers no advantage on mobile.
tipoo - Thursday, October 18, 2018 - link
It's already competing with laptop and desktop class chips, not just mobile fare. It's up there per core with Skylake server, and NOT normalized per clock, just core vs core.It's like people don't read these articles year over year and are still using lines from when A7 arrived...
tipoo - Thursday, October 18, 2018 - link
Only the A10X and A8X were 128 bit, on mobile that's still power limited for memory bandwidth.juicytuna - Friday, October 5, 2018 - link
Apple's big cores are like magic at this point. 2-3x the performance per watt of the nearest competitors is just ridiculous.sing_electric - Friday, October 5, 2018 - link
I know this is almost a side point, but this really goes to show what a mess Android (Google/Qualcomm) is compared to iOS. At the rate Snapdragon is improving, it'll be 2020/2021 before Qualcomm sells a chip as fast as 2017's A11, and Google is shooting itself in the foot by not having APIs available that take advantage of Snapdragon's (relative) GPU strength.That's on top of other long-term Android issues (like how in 2018, Android phones still can't handle a 1:1 match of finger movement to scrolling, which the iPhone could in 2008). Honestly, if I wasn't so invested in Android at this point, I really consider switching now.