ARM Cortex A9 vs ARM Cortex A15 – What to expect, and what’s the difference?

May 22, 2012

    ARM has completely dominated the mobile market for more than a decade, with over 90% market share, but it wasn’t until the rise of modern smartphones that we started to witness chips more powerful than anyone could have ever imagined we’d see in phones — chips that are now even starting to threaten Intel’s dominance and their status quo computing architecture.

    Starting with the ARMv7 architecture and the first Cortex CPU based on it, the A8, we already began to think of these devices as superphones or mini-computers once the 1 GHz barrier was broken. Then came the dual core Cortex A9 chips and, with them, brought a browsing experience with rich graphics similar to what was available on PC’s just 6 or 7 years before that, which is still very impressive when you consider it’s all done on a mobile phone.

    Fast forward to today, and we now have quad core Cortex A9 processors, and more. Despite this, I think many of us are already looking forward to the inevitable launch of chips based on the new Cortex A15 CPU, that promises to get ever closer to a level of performance that is good for laptops. this, all the while maintaining a low-power profile. So what can we expect from this next-gen chip compared to the Cortex A9 we’re using now?

    Performance

    If we go after DMIPS/Mhz, which might not be the best representation of performance,  then Cortex A9 has 2.5 DMIPS/Mhz, while Cortex A15 has 3.5 DMIPS/Mhz, and some manufacturers are even promising 4.0 DMIPS/Mhz. So, the performance per clock compared to Cortex A9 should be 40%-60% higher, all things being equal. This is a huge improvement in efficiency.

    Quick tip: DMIPS stands for Dhrystone Millions of Instructions per Second. 

    But things are not equal, so we should see Cortex A15 clocked at significantly higher frequencies as well. A dual core 2 GHz Cortex A15 chip like the upcoming Exynos 5250, should be around twice as fast a dual core 1.5 GHz¬†Cortex A9 chip. And that’s even for single threaded performance, not like current quad core Cortex A9 chips like the 1.5 GHz¬†Tegra 3 and 1.4 GHz¬†Exynos 4 Quad which should only have 15%-25% higher single threaded performance compared to last year’s dual core 1.2 GHz¬†Cortex A9 chips.

    What about multi-threaded performance? Just because you double the cores, doesn’t mean you get double the performance, except in very specific situations. Really though, on average, you should get about a 50% increase in performance (could be much lower or much higher for specific tasks and apps). To make a simple comparison: if a dual core 2 GHz¬†Cortex A15 is 2X faster than a dual core 1.5 GHz¬†¬†Cortex A9, we can still assume around 30% faster performance than today’s quad core processors for multi-threaded apps, even though it’s a dual core processor.

    New Features

    Unlike Cortex A9, which was supposed to go up to 2.0 GHz¬†per core (even though TSMC seems to have smashed that with their 3.1 GHz¬†per core frequency), Cortex A15 is supposed to reach 2.5 GHz¬†per core, something we’ll probably be able to see around mid-2013. Cortex A15 can also support up to 8 cores, compared to 4 for Cortex A9, so there’s room for growth there, too.¬†Unlike Cortex A8 and Cortex A9 which only supported the NEON extension optionally for media acceleration (Tegra 2 didn’t have it and it suffered for it), Cortex A15 will have NEON integrated by default.

    Although Cortex A15 is not a 64-bit processor, it can be extended to support up to 1 TB of RAM, which will be very useful in low-power servers. Another useful feature for servers, but also for those of us who like to juggle with many custom ROM’s or who might want to try another ROM without replacing their current one, is hardware virtualization. Of course this is something ROM makers would have to enable themselves for it to work, but I’m pretty excited about it, and it might even allow for faster upgrades for Cortex A15-based devices.

    GPU

    The first chip with a Cortex A15 CPU should be the Exynos 5250, and it’s expected to land sometime this summer or early fall. Although, it might appear as a dual core 1.7 GHz¬†version, perhaps even in the upcoming Google tablet that will be announced at Google I/O. However, don’t get your hopes up to much, because Samsung might not want other companies (Asus) to be the first ones to use this chip.

    It’s also expected to be integrated into¬†Samsung’s 2560×1600 resolution tablet, the full 2 GHz¬†version and with the Mali T-604, which should be the most powerful GPU this year by far. It should even handily beat the Adreno 320 if it’s only going to be 2X as fast as Adreno 225 as I suspect it will be. The Mali T-604 will be the perfect GPU for Cortex A15, thanks to the high integration with it, since both are made by ARM.

    The Mali T-604 GPU promises 5x the performance of Mali 400 (the one in GS2, not GS3) will support Google’s Renderscript which is used to hardware accelerate the Android 4.0 UI and OpenCL. This can be used for much improved graphics, smarter AI in games, real time augmented reality apps and image processing, and so on.

    Big.Little

    What’s even more exciting is that Samsung might be using Cortex A15 in their Nexus phone this fall, and it might not even be the Exynos 5250 per se, but a variant using Cortex A7 as well and the big.Little configuration for heterogeneous computing. I’m cautiously optimistic about this one because even though Cortex A7 is not supposed to appear until 2013, Samsung has mentioned before they will ship Cortex A7 this year.¬†This feat and revelation is brought to us thanks to their close relationship to ARM.

    The simple truth, for smartphones especially, you’re going to need something like a single core or even dual core Cortex A7 to make things more efficient for simple tasks. The exceedingly powerful Cortex A15 doesn’t have to wake up and use more battery. I’m also excited about Cortex A7 because I hope it’s going to replace the ancient ARM11 once and for all. It should enable a market for sub-$100 fast Android smartphones with dual core Cortex A7 chips.

    The Future

    While I’m very excited about the Cortex A15, Mali T-604 and Cortex A7, I’m even more excited for¬†ARMv8 architecture, and new chips such as the successors of Cortex A15, Mali T6xx and Cortex A7 that will appear starting in 2014. ARM has been getting enormous demand for their ARMv8 architecture, which is still a couple of years away; the support for the 64 bit ARM architecture will be there from day one, rather than still having weak support for it many years later. This is the unfortunate case with Intel and AMD’s 64 bit architectures and this is why they lag behind in a market they helped initially create.

    Whatever this means for Android, we shall see, but since everyone is going to support it, including the Linux community, and this means that many Linux operating systems will work by default on all future 64 bit chips! Potentially, it might make Android upgrades and installing Android on different devices a lot easier, too.

    Any thoughts on all of this?

    Comments

    • sn0wbaLL

      and it’s only gonna get better:)

    • tomn1ce

      WOW….just WOW…..I like the way ARM is working on improving their chips…I’m amazed at what my phone can do right now…I can’t imagine how easy it will be able to do the current tasks at hand and the future task assigned to it in a few years….I know there’s some speculations in the article but just knowing that things will get way batter down the road is just blows my mind…I know that with time tech advances and is a good to read articles like this….

    • AppleFUD

      Great article. . . the kind of article I love to see on AA!

      The A15 SoC are the one thing that has me excited this year. . . well, for mobile tech that is ;)

      I think the A15 can push Android onto a laptop to replace current Intel middle and lower end laptops and allow for some heavier apps for productivity. Imagine how much cheaper a device can be when you aren’t paying Intel’s high markup for a chip. . . and NO fan!

      IMO we wouldn’t be seeing this fast increase in SoC tech if it were not for Android ‚ÄĒ Nokia, RIM, and apple would have happily taken the slow route and there would have been no “arms race” for SoC performance as we have now ‚ÄĒ you have gotta love that competition factor.

      While the 64bit ARM architecture is something to drool over it’s a little far off. . .

      • https://plus.google.com/117702410245683101961/posts Lucian Armasu

        Yes, probably not since Apple is more interested in increasing GPU performance than CPU performance lately through larger chips because of their relationship with Imagination, and WP7 so far has used 2 year old chips and only from one company. So I do think there would be some stagnation in the ARM CPU market if only iOS and WP7 were the players. RIM and Nokia haven’t liked using the latest chips either in the past few years.

        • hot_spare

          Great write-up Lucian!

      • Ah Dee

        Why would you ever want android on a laptop over a full feature version of linux/windows/osx? Do you LIKE to flush money on 1.99 apps to do the work of FREE SOFTWARE?

        • Derp

          I honestly think that Google could find a way to tweak Android as much as to make a mobile version, a tablet version, and a laptop version.

        • Someone

          There are free software (open source) on Google’s Play store available… for free… Not sure what you’re talking about.

          I’m looking forward to the hybrid Windows(or *nix)/Android devices. =)

        • HappyNonconformist

          While Android on a laptop may be obscene, ARM in a laptop is very much welcome to me. I refuse to use x86 in any of my personal machines (call me a bigot), so a replacement to my aging G4 laptops is very welcome.

    • http://www.facebook.com/people/Jean-Luc-Aufranc/100000690503162 Jean-Luc Aufranc

      Nice article. It would also have been nice to mention Cortex A5, although it’s not as widespread and popular as the others.

    • Guest_from_canada

      so you saying it will be in Snapdragon S4 APQ8064?

    • http://www.facebook.com/tioz90 Thomas Tioz Tiotto

      When are we going to start seeing quad core A15 chips?

    • http://www.facebook.com/profile.php?id=1380039246 Dhruv Sahni

      great article

    • http://www.facebook.com/profile.php?id=100000738940938 Moosa Mahsoom

      haswell should crush cortex a15 and ARM V8. it’s said to be in the same TDP as ARM.

      • http://ARMdevices.net/ Charbax

        haswell has been leaked, uses 160W, 190Amps, it uses 100x more power than ARM Cortex-A15 and ARMv8, Intel has nothing.

        • Wyler Chesterfield

          You just said something either pulled right out of your rear, or heard something stupid from someone/where else without doing any research at all. ( Trolling maybe? )

          160w? Maybe in some extreme overclocked part or a multicore top-tier server chip ( MAYBE ).

          The rest will run at a small fraction of that.

          What a FUDdy post.

    • Jon1123

      Kind of misleading. The omap 5 will hav the fastest gpu by far followed by the a5x then by this. Wile they all hav the same fill rate the omap 5 and a5x are much better with geometry.

    • http://www.facebook.com/BjornOle Bj√∂rn-Ole Antonsen

      When will there be desktop CPUs from ARM? Intels have not worked well for many years and AMD has given up the performance race..

      • Carl

        ARM CPUs was initially designed for desktops (Old Acorn Machines, replacing the 6502 CPU in the BBC). 1 Legacy (still exists) feature of the arm is the ability to push unknown instructions on to a 2nd cpu of a completely different architecture completely by hardware. What I’m waiting for is a modern Desktop OS to run under ARM and when needed send the commands onto a x86/PowerPC. This was being done in the 90s and is how i assume Wii works the ARM cpu (inside) sends the PowerPC code to the main CPU.

    • john

      OK my Gurus you were allright, today we know iphone 5 has 2 A15 working in his new phone, what thats means? do they beat samsung note 2 quad core?

      • ari_free

        Actually Apple isn’t using A15 but rather their own A6.

        • KyleRay

          How many times have we heard this? When Galaxy S’s Hummingbird and even before that, all Apple’s iPhones were powered by Samsung’s superior chips. Why? ….because they knew their stuff and didn’t just rip off the credit for inventing everything in the World! …..as it turned out, under an electron microscope there was no difference between Hummingbird and Apple A4. Yet Apple insisted that they invented it and Samsung steals everything from them!

          LG’s technology is what Retina was built on. But do you think for a moment Apple would ever give them credit? Hell NO! Samsung again came to Apples rescue when they chose to take the cheaper route on Retina for iPad 3. This time it was Sharp’s legacy SHA technology they resurrected from the dead. But neither Sharp nor LG could get the job done. In comes Samsung to save the day, even though Apple has never been grateful for anything they’ve ever done for them.

          Now we have another reason to suspect that Apple in reality has never really invented or innovated one single thing, that they didn’t Rip Off others and claim it as their own. The Biggest Hypocrites in the World with the Largest Brain Dead Followers since the Koolaid drinkers following Jim Jones into Purgatory!

          The A6 CPU cores are custom alright, Qualcomm custom cores that is!!!
          https://ar.qualcomm.at/content/when-can-we-expect-update-which-allows-use-armv7s

          Apple says, “We invented the sun the moon and the stars above. Since our most exalted Saint Steve ‘The Royal Con’ Jobs died, we now have “Sir Jony Ive invented everything” to make sure all YOU iDIOTS keep pouring your money into our iChurch Coffers. So we can invest in our retirement, held in off shore banking. For when the Feds finally catch on to our Greedy Money Grubbing Scams and Schemes ripping you all off!” ;-P

    • Guest

      I’m reading this ,5 years later, his interpretation of the tech and the market was spot on.

    • Marc Abelha

      I’m reading this 1,5 years later, his interpretation of the tech and the market was spot on.

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