The iPhone 5 Review
by Anand Lal Shimpi, Brian Klug & Vivek Gowri on October 16, 2012 11:33 AM EST- Posted in
- Smartphones
- Apple
- Mobile
- iPhone 5
General Purpose Performance
Section by Anand Shimpi
Apple's philosophy on increasing iPhone performance is sort of a mix between what Microsoft is doing with Windows Phone 7/8 and what the high-end Android smartphone makers have been doing. On the software side Apple does as much as possible to ensure its devices feel fast, although I notice a clear tendency for newer iOS releases to pretty much require the latest iPhone hardware in order to maintain that speedy feel over the long haul. When it comes to hardware, Apple behaves very much like a high-end Android smartphone vendor by putting the absolute fastest silicon on the market in each generation of iPhone. The main difference here is that Apple controls both the software stack and silicon, so it's able to deliver a fairly well bundled package each year. It's a costly operation to run, one that is enabled by Apple's very high profit margins. Ironically enough, if Apple's competitors would significantly undercut Apple (it doesn't cost $599 - $799 to build a modern smartphone) I don't know that the formula would be able to work for Apple in the long run (Apple needs high margins to pay for OS, software and silicon development, all of which are internalized by Apple and none of which burden most of its competitors).
Good cross platform benchmarks still don't really exist on smartphones these days. We're left describing experience with words and trying to quantify performance differences using web based benchmarks, neither of which is ideal but both of which will have to do for now. The iPhone 5 experience compared to the 4S is best explained as just being snappier. Apps launch faster, scrolling around iOS Maps is smoother, web pages take less time to load and the occasional CPU/ISP bound task (e.g. HDR image processing) is significantly quicker. If you're the type of person who appreciates improvements in response time, the iPhone 5 delivers.
How does it compare to the current crop of high-end Android smartphones? I would say that the 5 generally brings CPU performance up to par with the latest and greatest in the Android camp, and in some cases surprasses them slightly. It's difficult making cross platform comparisons because of huge differences in the OSes as well as separating out tasks that are CPU bound from those that simply benefit from a higher rendered frame rate.
I took a cross section of various web based benchmarks and looked at their performance to help quantify where the iPhone 5 stands in the world. First up are the RIABench focus tests, these are javascript benchmarks that focus on various compute bound tasks. I used Chrome for all Android devices to put their best foot forward.
This first test shows just how slow the 800MHz Cortex A9s in the iPhone 4S were compared to the latest and greatest from Qualcomm and NVIDIA. At roughly half the clock speed of those competitors, the 4S was just much slower at compute bound tasks. Apple was able to mask as much of that as possible with smooth UI rendering performance, but there was obviously room for improvement. The iPhone 5 delivers just that. It modernizes the iPhone's performance and inches ahead of the Tegra 3/Snapdragon S4 platforms. Only Intel's Atom Z2460 in the Motorola RAZR i is able to outperform it.
Next up is Kraken, a seriously heavy javascript benchmark built by Mozilla. Kraken focuses on forward looking applications that are potentially too slow to run in modern browsers today. The result is much longer run times than anything we've seen thus far, and a very CPU heavy benchmark:
The standings don't change much here. The iPhone 4S is left in the dust by the iPhone 5, which steps ahead of the latest NVIDIA/Qualcomm based Android devices. The Apple advantage here is just over 10%. Once again, Intel's Atom Z2460 pulls ahead with the clear lead.
In our iPhone 5 Performance Preview we looked at Google's V8 javascript test as an alternative to SunSpider. The more data points the merrier:
Here the iPhone 5 manages to hold onto its second place position, but just barely. Once more, the Atom based RAZR i maintains the performance lead.
Google's Octane benchmark includes all 8 of the V8 tests but adds 5 new ones including a PDF reader, 3D bullet physics engine and portable 3D game console emulator all built in javascript.
The 5 pulls ahead of the HTC One X here and maintains a healthy 31% lead, but once again falls short of the RAZR i.
We of course included our SunSpider and BrowserMark tests, both of which show the iPhone 5 very favorably:
Performance obviously depends on workload, but it's clear the iPhone 5 is a big step forward from the 4S and tends to outperform the latest ARM based Android smartphones. As the rest of the ARM based SoC players move to Cortex A15 designs they should be able to deliver faster devices in the first half of 2013.
Intel's current position when it comes to CPU performance is interesting. A move to a dual-core design could be enough to remain performance competitive with 2013 ARM based SoCs. Remembering that Atom is a 5 year old CPU core that performs at the level of a 10 year old mainstream notebook CPU puts all of this progress in perspective. Intel's biggest issue going forward (other than getting Atom into more tier 1 phone designs) is going to be improving GPU performance. Luckily it seems as if it has the roadmap to do just that with the Atom Z2580.
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themossie - Tuesday, October 16, 2012 - link
The manufacturer's charger uses a set of pull-up resistors connected between the various USB lines, to indicate that the phone can pull maximum current. Unfortunately, every manufacturer (and sometimes different phones) use different resistances.See http://electronics.stackexchange.com/questions/144... for a brief writeup.
For what it's worth, I've only had this problem with iDevices and the HP Touchpad. I own circa-2011+ HTC, Motorola and Samsung phones, and they all work fine with every charger. My Droid 2 Global was my primary work phone until a few months ago, and works great with every charger. Not sure why your wife is having problems there.
crankerchick - Tuesday, October 16, 2012 - link
"The non-LTE phones see a sharp drop in battery life. At least at 28nm the slower air interfaces simply have to remain active (and drawing power) for longer, which results in measurably worse battery life. Again, the thing to be careful of here is there's usually a correlation between network speed and how aggressive you use the device. With a workload that scaled with network speed you might see closer numbers between 3G and 4G LTE."Perhaps you all could devise a test for this? Something like, change your LTE and 3G tests, where you decrease the time between page loads for the LTE test, to simulate doing more browsing since the pages load faster? One data point on this, with a reasonably selected change in page load duration, would be very helpful now that we have this very interesting dynamic clearly visible.
That said, as always, I appreciate the reviews presented here. Always thorough with lots of information to chew on beyond specs and "user opinion on user experience."
Just wish the reviews didn't take so long, but they are always worth it in the end.
TofDriver - Tuesday, October 16, 2012 - link
Thanks for this awesome article. Gigantic work, we'll worth the wait.I've learnt so much.
Would still appreciate it as an ebook, even after the web reading!
Seems like you're perfectionists who love to push limits... To me it does resonate with the team who designed the reviewed product.
name99 - Tuesday, October 16, 2012 - link
"Another potential explanation is that the 3-wide front end allowed for better utilization of the existing two ALUs, although it's also unlikely that we see better than perfect scaling simply due to the addition of an extra decoder."Remember the standard numbers. On this type of integer code:
1/6 instructions are branch
1/6 instructions are store
1/3 instructions are load
1/3 instructions are ALU
This means the usual first throttling point i cache access, if you can only do one load/store cycle.
If you limit your cache to one op/cycle, it's generally not worth going beyond 2-wide --- too often you're waiting on the cache.
Once you widen your cache (usually, at this stage, by allowing simultaneous read and write per cycle) three-wide makes sense.
Each cycle now (on ideal and some sort of "average" idealized code) you can now do some sort of combination of half a branch, 1.5 load/stores, and 1 ALU. Meaning that 2 ALUs (as long as they are not overloaded and also handling some aspect of the load/store) is enough for now.
[Of course things never work out quite this ideal --- you have burstiness in operation types, not to mention delays. But the compiler should try to schedule instructions to get this sort of average, and likewise the re-order queues will do what they can to shuffle things to this sort of average. 2ALUs helps with the bursts, 3ALUs is overkill.]
So I would say the primary important change made to go to three-wide in a way that is not a waste of time was to convert the L1 cache to dual-ported, supporting simultaneous load & store per cycle.
jiffylube1024 - Tuesday, October 16, 2012 - link
I have to commend the Anandtech team for the great review! It was a long wait, but well worth it. The info on anodizing, the "Swift" CPU @ 1.3 GHz, camera performance, etc. was worth waiting for. This article, in my eyes, is a culmination of the Anandtech team's knowledge in the tech industry - deconstructing A6 to figure out what it's made of, discussing Apple's manufacturing capabilities, etc. Very informative and well written!I am always amazed at how many complaints (and petty platform wars) get exposed on the comment board. I certainly appreciate them when an article is poorly written, contains false information or outright lies, but with an article like this, the comments section seems shy of the effusive praise it deserves!
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On a slight tangent, I've enjoyed the first 8 Anandtech podcasts as well, and I have to say that I look forward to more non-iPhone related disucssion on future podcasts. The information was much appreciated, but for a tech site as broad as Anandtech, the first 8 podcasts have been VERY iPhone heavy in their content! Keep up the good work.
jamyryals - Thursday, October 18, 2012 - link
I think you're right, it has been iPhone heavy, but the start of the podcast kind of lined up with the launch/review process. Let's be honest, it is a huge selling high quality device and it's treated as such. I have a feeling Brian and Anand will have a lot to say about all of the impending Nexii/WP8 when they come out this quarter.krumme - Tuesday, October 16, 2012 - link
Good to see reviewers apreciation of low light capabilities for the BSI sensor, reflecting real world usage. Oposite to a lot of uninformed stupid reviews on the net.Its exactly the same practical difference between s2 and s3 cameras. Big difference for real usage.
All the mpix race must stop now. 8M is way to much for the quality anyway.
Zanegray - Tuesday, October 16, 2012 - link
I love the level of analysis and attention to detail. Keep it up!mrdude - Tuesday, October 16, 2012 - link
Wow, what an article. Really fantastic read. The lengths you guys have gone to in this review is stunning, frankly. Well done. Although I'm no Apple fanatic, I must say that this is one of the better articles I've read on AT :)Dennis Travis - Tuesday, October 16, 2012 - link
Totally outstanding review. You guys covered everything. Thanks so much!