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Relative Performance of ARM Cortex-A 32-bit and 64-bit Cores

Many people assume newer processors will be faster, or that 64-bit processor will provide a performance boost compared to 32-bit processors, but the reality can be quite different, and I’ve decided to have a look at ARM Cortex-A cores using ARMv7 (32-bit) and ARMv8 (64-bit) architecture, and see what kind of integer performance you can expect from each at a given frequency. To do so, I’ve simply use DMIPS/Mhz (Dhrystone MIPS/Megahertz) values listed on Wikipedia.

Vertical Scale: DMIPS / MHz

Vertical Scale: DMIPS / MHz


Drystone benchmark has no floating-point operating, so it’s a pure integer benchmark. I’m only looking at ARM core here, and once integrated in an SoC, other parameters like memory bandwidth, amount of cache,  GPU, etc.. will greatly affect the overall system performance. The figure above are per MHz, and it does not mean for example that a Cortex A5 processor will be slower than a Cortex A7 processor, as can be seen by the comparison between Amlogic S805 (4x Cortex A5) and Broadcom BCM2835 (4x Cortex A7), which shows the Amlogic processor is about 40% faster due to higher clock speed.

With that in mind, it can be seen than you may not expect all recent Cortex A53 processors to outperform existing Cortex A15 and A17 processors, and in some case even Cortex A9 processors, and the real performance benefit with 64-bit cores only start to show with Cortex A57, and especially Cortex A72 cores which is some cases could be twice as fast as Cortex A15 cores. The red zone on top of some bars represents the possible performance variation due to different implementations of the cores.

ARMv8 also brings some other improvement such as additional cryptographic extensions, an increase in the number of SIMD/floating point, and general purpose registers, and more, as shortly explained in that article. All of these should also deliver benefits provided the firmware and applications support them.

  1. kcg
    April 9th, 2015 at 15:36 | #1

    the graph looks sensible with just little detail and this is difference between A15 and A17 performance. A17 is just fine-tuned A15 so it should be the same or little bit better IMHO.

  2. RAF
    April 9th, 2015 at 15:58 | #2

    Well on the mighty Internet have you found to say that Cortex A17 is 3 DMIPS/Mhz? Also based on ARM information Cortex A7 has 90% of a Cortex A9 so I really doubt about Cortex A7 being under Cortex A8. Also according to ARM Cortex A53 is 30-40% faster the Cortex A7 on the same process, which would make it 20% faster than Cortex A9.
    Also techreport says it “In fact, ARM tells us the A53 is roughly 15% faster than the mid-sized Cortex-A9 rev4.”

    http://www.arm.com/White_Background_PNG_Cortex-A7.png
    http://www.arm.com/Performance_Graph_A53_to_A7.jpg

    So I would conclude your graph is deeply flawed.

  3. April 9th, 2015 at 16:09 | #3

    @kcg
    I could not find the figures for A17, only for A12, and I understood both just have the same performance… so ARM even phased out A12.

    @RAF
    The source is Wikipedia as stated in the article…

  4. April 9th, 2015 at 17:09 | #4

    Anandtech has a table with about the same numbers, including Cortex A9 > Cortex A53, except for Cortex A17, so I’ll update the chart with 4.0 instead of 3.0.
    http://www.anandtech.com/show/7739/arm-cortex-a17

  5. Marius Cirsta
    April 9th, 2015 at 17:47 | #5

    It would be nice to see some real world performance figures for these, not from Android benchmarks line Antutu but from some benchmarks running on Linux.

  6. GMR 73
    April 9th, 2015 at 19:37 | #6

    I am interested to know more about the red zone, is that related to manufacturing process or core revision? I have noticed the later A15 revisions like in the Tegra K1 have a big improvement in power consumption over the early versions ie Tegra 4. A72 looks like it’s going to be a Chromebook champion considering that my Tegra K1 HP is already more than powerful enough.

  7. April 9th, 2015 at 19:49 | #7

    @GMR 73
    I got the range on Wikipedia. For example with Cortex A72: “At least 6.3 DMIPS/MHz per core (up to 7.35 DMIPS/MHz depending on implementation)”, and unfortunately I don’t know the reason.

  8. RAF
    April 10th, 2015 at 02:32 | #8

    So you are concluding wikipedia (which I do not totally trust, because any one can post on wikipedia if that is what he really want) and anandtech (which indeed is a pretty accurate source of information) are more reliable than ARM slides?

  9. April 10th, 2015 at 02:35 | #9

    It really gets interesting with Cortex-A57 octa core like the Nvidia Tegra X1
    http://bitkistl.blogspot.co.at/2015/03/cortex-ax-vs-performnace.html

  10. Al
    April 10th, 2015 at 06:52 | #10

    Bring on the low cost A54 and A72 boards and gadgets so we can all do “testing”!!

  11. April 10th, 2015 at 09:12 | #11

    @RAF
    I think they are two different set of data. I’m using Drystone MIPS data, which Anandtech says comes from ARM, but I could not find it on ARM website, while the ARM chart you provided must be using some other benchmarks, but they did not specify which one. If I have data for Cortex A5 to Cortex A72 with these benchmarks, I could make an alternative chart.

    DMIPS/MHz for A7 is 1.9, for A53 2.3, so a difference of about 21% against 30% integer performance on ARM charts. So not quite exactly the same, but not such a massive difference either.

  12. April 21st, 2015 at 16:40 | #12

    Cortex A15 and A17 may have the same integer performance (DMIPS/Mhz or SpecInt2k), but Cortex A17 is faster for web browsing. http://community.arm.com/groups/processors/blog/2015/04/20/cortex-a17-powers-new-generation-of-chrome-os-devices

  13. RAF
    June 10th, 2016 at 19:41 | #13

    http://images.anandtech.com/graphs/graph9878/79519.png
    Only problem is that Cortex A9 is missing.

  14. theguyuk
    September 2nd, 2016 at 23:23 | #14

    So if Rockchip could match AMLogic (cheats ), S905 prices with their RK3288 and Android 6 or 5.1.1 things could get really interesting?

    AMLogic could be given a bloody nose. Can RK3288 match or get close to S905 power consumption?

  15. sonu
    September 16th, 2016 at 11:53 | #15

    which means cortexa9(32bit) is better then cortex a53(64bit)

  16. Meth
    February 21st, 2017 at 23:06 | #16

    So A17 >> A53 .. and if RK3229 runs 1.8GHz and RPI3 runs 1.2GHz then the TinkerBoard SHOULD be a real 2x performance of RPI3 in real world apps.. emulatioN????

  17. tkaiser
    February 22nd, 2017 at 01:12 | #17

    @Meth
    Regarding raw CPU performance Tinkerboard will be twice as fast as RPi 3. Numbers are already available, just use search bar in the upper right corner for an older blog post ‘Android and Linux Benchmarks on MiQi Development Board’ and keep in mind that some numbers might have been affected by throttling back then.

    RK3288 can be ‘overclocked’ to 2GHz too but then you need to take care about appropriate power supply and heat dissipation. Search the web (or directly mqmaker forum) for ‘MiQi-based build farm finally up and running’ to get the idea what’s necessary to do number crunching on these devices. Though RPi 3 could be somewhat faster here (Cortex-A53 CPU cores can make use of ARMv8 instruction set) but RPi foundation thinks it is a good idea to provide only software compiled with an outdated GCC for ARMv6 instruction set.

    BTW: ‘Real world’ performance is not only about CPU performance, there’s a lot more to be considered (amount of DRAM and memory bandwidth for example, access to storage and if you’re using networking then every RPi is simply a joke with its crippled USB-Ethernet). And as soon as ‘media’ and ‘gaming’ are use cases the other parts of the SoC and driver situation become more and more important (VPU/GPU stuff — you need to overclock an RPi 3 to decode HEVC video in 1080p while RK3288 can decode this in higher resolutions VPU accelerated if drivers are available)

  18. theguyuk
    February 22nd, 2017 at 02:06 | #18

    @Meth
    Tinker board runs RK 3288 not RK3299 = Quad A7 core
    Tinker board upscales 1080 for 4k @30fps

    http://www.cnx-software.com/2017/01/05/asus-tinker-board-is-a-raspberry-pi-3-alternative-based-on-rockchip-rk3288-processor/

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