SPEC2006 Perf: Desktop Levels, New Mobile Power Heights

Given that the we didn’t see too many major changes in the microarchitecture of the large Lighting CPU cores, we wouldn’t expect a particularly large performance increase over the A12. However, the 6% clock increase alongside with a few percent improvement in IPC – thanks to improvements in the memory subsystems and core front-end – could, should, and does end up delivering around a 20% performance boost, which is consistent with what Apple is advertising.

I’m still falling back to SPEC2006 for the time being as I hadn’t had time to port and test 2017 for mobile devices yet – it’s something that’s in the pipeline for the near future.

In SPECint2006, the improvements in performance are relatively evenly distributed. On average we’re seeing a 17% increase in performance. The biggest gains were had in 471.omnetpp which is latency bound, and 403.gcc which puts more pressure onto the caches; these tests saw respective increases of 25 and 24%, which is quite significant.

The 456.hmmer score increases are the lowest at 9%. That workload is highly execution backend-bound, and, given that the Lightning cores didn’t see much changes in that regard, we’re mostly seeing minor IPC increases here along with the 6% increase in clock.

While the performance figures are quite straightforward and not revealing anything surprising, the power and efficiency figures on the other hand are extremely unexpected. In virtually all of the SPECint2006 tests, Apple has gone and increased the peak power draw of the A13 SoC; and so in many cases we’re almost 1W above the A12. Here at peak performance it seems the power increase was greater than the performance increase, and that’s why in almost all workloads the A13 ends up as less efficient than the A12.

In the SPECfp2006 workloads, we’re seeing a similar story. The performance increases by the A13 are respectable and average at 19% for the suite, with individual increases between 14 and 25%.

The total power use is quite alarming here, as we’re exceeding 5W for many workloads. In 470.lbm the chip went even higher, averaging 6.27W. If I had not been actively cooling the phone and purposefully attempting it not to throttle, it would be impossible for the chip to maintain this performance for prolonged periods.

Here we saw a few workloads that were more kind in terms of efficiency, so while power consumption is still notably increased, it’s more linear with performance. However in others, we’re still seeing an efficiency regression.

Above is a more detailed historical overview of performance across the SPEC workloads and our past tested SoCs. We’ve now included the latest high-end desktop CPUs as well to give context as to where the mobile is at in terms of absolute performance.

Overall, in terms of performance, the A13 and the Lightning cores are extremely fast. In the mobile space, there’s really no competition as the A13 posts almost double the performance of the next best non-Apple SoC. The difference is a little bit less in the floating-point suite, but again we’re not expecting any proper competition for at least another 2-3 years, and Apple isn’t standing still either.

Last year I’ve noted that the A12 was margins off the best desktop CPU cores. This year, the A13 has essentially matched best that AMD and Intel have to offer – in SPECint2006 at least. In SPECfp2006 the A13 is still roughly 15% behind.

In terms of power and efficiency, the A13 seemingly wasn’t a very successful iteration for Apple, at least when it comes to the efficiency at the chip’s peak performance state. The higher power draw should mean that the SoC and phone will be more prone to throttling and sensitive to temperatures.


This is the A12, not A13

One possible explanation for the quite shocking power figures is that for the A13, Apple is riding the far end of the frequency/voltage curve at the peak frequencies of the new Lightning cores. In the above graph we have an estimated power curve for last year’s A12 – here we can see that Apple is very conservative with voltage up until to the last few hundred MHz. It’s possible that for the A13 Apple was even more aggressive in the later frequency states.

The good news about such a hypothesis is that the A13, on average and in daily workloads, should be operating at significantly more efficient operating points. Apple’s marketing materials describe the A13 as being 20% faster along with also stating that it uses 30% less power than the A12, which unfortunately is phrased in a deceiving (or at least unclear) manner. While we suspect that a lot of people will interpret it to mean that A13 is 20% faster while simultaneously using 30% less power, it’s actually either one or the other. In effect what this means is that at the performance point equivalent to the peak performance of the A12, the A13 would use 30% less power. Given the steepness of Apple’s power curves, I can easily imagine this to be accurate.

Nevertheless, I do question why Apple decided to be so aggressive in terms of power this generation. The N7P process node used in this generation didn’t bring any major improvements, so it’s possible they were in a tough spot of deciding between increasing power or making due with more meager performance increases. Whatever the reason, in the end it doesn’t cause any practical issues for the iPhone 11’s as the chip’s thermal management is top notch.

The A13's Memory Subsystem: Faster L2, More SLC BW System & ML Performance
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  • michael2k - Wednesday, October 16, 2019 - link

    You're asking that the phone under report it's battery reserve and shut the phone down at 40% battery to preserve battery longevity?

    Because that would be the effect. So instead of a battery that lasts 14 hours for the first year and then 10 hours the second, it would 'shut down' after 11 hours the first year, and 'shut down' after 11 hours the second year, and 'shut down' after 11 hours the third year, before the degradation actually causes the battery life to actually be 10 hours in year four.
    Reply
  • melgross - Wednesday, October 16, 2019 - link

    Wow! That makes no sense. All phones slow down over time, and all batteries hold less charge. Apple’s are t worse, if anything, they’re better. My Max, from last year still reads 100% on battery health after more than 11 months of fairly heavy daily use. I’d like to see other phones that do better. Reply
  • shompa - Thursday, October 17, 2019 - link

    Look at intel /AMD / Qualcomm. They list a "turbo speed" that is not guaranteed. But customers believe it is. That's why they don't need to downclock stuff because they never need to hit their speeds. Apple is the last vendor having a real CPU speed and holds it. I have had a multitude of Intel CPUs that under-deliver in speed and as a customer you can't do anything. The service centers simply don't understand the problem since they only do a CPID check and says "it works". Take any intel laptop and fire up an H265 encode and watch the CPU speed go down. A CPU labeled 2.9ghz /3.9ghz turbo suddenly is a 2ghz part and you can't do anything about it. At least with Apple: get a good battery and it works. Reply
  • Total Meltdowner - Wednesday, October 16, 2019 - link

    All for the low low price of $1300. Pass. Reply
  • Zerrohero - Wednesday, October 16, 2019 - link

    $999 actually.

    This is a device that you can use for five years, or more, always with the latest software. Just get the battery replaced once.

    Amazing value, as iPhones always are.
    Reply
  • Total Meltdowner - Thursday, October 17, 2019 - link

    Nice troll brother. But a full loaded iPhone 11 Pro is $1299.

    iPhones are trash.
    Reply
  • Total Meltdowner - Thursday, October 17, 2019 - link

    Sorry, it's $1450! LOL!

    Almost $1800 with applecare! https://www.apple.com/shop/buy-iphone/iphone-11-pr...

    ahahahahahahha
    Reply
  • Irish910 - Friday, October 18, 2019 - link

    You can get an iPhone 11 with 128 gigs for $749, which pretty much mops the competition with battery life, CPU, GPU, longevity and value.

    I know your troll self will say something like “BR0 it’s only GoT a 720P scr33n, my 2015 GaLaXy HaS h1gher Res0lution!

    Fact is, most people don’t care about that. That’s why the XR was the most popular phone last year and that trend will continue.

    The pro starts at $999. Stop trolling. This site is for adults only. If you only post your lame hate comments, please go to YouTube. There’s plenty of room for your kind there.

    Shoo shoo now.
    Reply
  • Quantumz0d - Wednesday, October 16, 2019 - link

    This analysis is great but the Whiteknighting is insane.

    The design the primary aspect of a device, the display itself is notched no matter what calibration it has it's destroying the proper nature of how we perceive through our eyes and mind. Dead pixel zone for $999

    No expandable storage, No Filesystem access - Must use iTunes. This means for every basic work you must rely on your computer and the iCloud, mega ecosystem lockdown.

    No 3.5mm jack. Its really a shame how this company made billions by buying up Beats (Sub par garbage audio) and AirPods ($179 of Sub 320kbps audio with limited life due to Li Ion) and making a dongle business out of an Analog standard and whole industry reeks of this greed by dongles snd their own BT products which are massively inferior in sound snd usage and also wear down the only port it has.

    Sealed battery, Strong adhesive with new 4m depth rating. $600 for back glass repair if no Apple care and they are forcing you to buy because its $300 only and 70USD per repair. More profit for Apple for $100 battery services. Unfortunate that Apple has brick and mortar rest do not but they want to siphon off. Also did author note how iPhone XS got the new battery throttling with latest iOS update ? Yeah bonus package to wreck all that performance, inherent overdrawing of Voltage and planned obsolescence.

    Too much of this price hike and offering measly 64GB base. Next year another $50-100 due to new design or whatever they want to call.

    Desktop performance. I want to see, can this A series chip run an Adobe CS6 or Blender or do a H264 Conversion faster or on par with a desktop chip ? Or play high refresh rate gaming or can it execute x86 instructions with ease and replace my PC with this BGA pile of junk ? (It cannot, I think it's too much of blowing into this hot balloon of Apple for mega limelight) same for 9900K or 3950X they can't be fit in a pocket.

    Finally the corporation of American back, has no backbone when it comes to China. The $$$$ speaks. Censorship and aiding the Orwellian draconian principles for cash is more than the American culture that spawned the company and its people. A big shame.
    Reply
  • Total Meltdowner - Wednesday, October 16, 2019 - link

    Bingo. I think the writer was just happy that he did notice performance improvements in this model. Still, the iPhone lacks innovation and that price tag is absurd. I'd buy it for $600 but $1000 or more? hah! Reply

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