Snapdragon 820 Performance Preview

Snapdragon 820 Architecture

Qualcomm has remained tight-lipped about its latest processor designs. Unlike ARM’s full-disclosure model, Qualcomm is much more Apple-like when it comes to releasing low-level information, particularly about its GPUs.

While technical details are in short supply, our curiosity about Snapdragon 820’s most interesting component—the 64-bit Kryo CPU core—remains high. The move from TSMC's 20nm HKMG planar process to Samsung’s 14nm FinFET process should mitigate the thermal issues experienced by Snapdragon 810 and allow the 820 to use less power and/or reach higher clock speeds. According to Qualcomm, with the “Kryo CPU and Snapdragon 820, you can expect up to two times the performance and up to two times the power efficiency” when compared to the A57 CPU in Snapdragon 810. This is certainly a bold claim, but based on the overheating issues we observed with the 810, coupled with the excellent performance from Samsung’s Exynos 7420 SoC, which uses Samsung’s first-generation 14nm LPE (Low Power Early) FinFET process, it might be possible. It’s not clear if the 820 will use LPE or Samsung’s second-generation 14nm LPP (Low Power Plus) FinFET process, which, according to Samsung, can achieve 10% higher frequency at lower power than LPE because of a better fin aspect ratio.

As mobile workloads continue to evolve, so do mobile SoCs. One parameter in constant flux is the optimal number of CPU cores, with designs ranging from Apple’s A9, which uses two CPU cores, to MediaTek’s Helio X20, which uses ten CPU cores in a tri-cluster, big.LITTLE arrangement. According to Tim McDonough, Qualcomm's VP of Marketing, “people don't really need more than four cores.” While this statement will likely spark some heated debate, Qualcomm’s data seems to be pointing it in that direction since the Snapdragon 820 uses four Kryo CPU cores in a dual-cluster, heterogeneous configuration. While the underlying architecture of each CPU core is the same, the clusters are optimized to operate at different frequencies and power levels, sort-of like ARM’s big.LITTLE approach. The two Kryo cores in the lower-power “Silver” cluster operate at frequencies up to 1.6GHz and share a 512KB L2 cache. The second pair of Kryo cores in the higher-performing “Gold” cluster operate at frequencies up to 2.2GHz and share a 1MB L2 cache. While L2 cache is not shared between the Gold and Silver clusters, the two L2 caches use a snooping mechanism to maintain coherency. Unlike Apple’s A9, Snapdragon 820 does not use an L3 cache. Qualcomm says it considered using an L3 cache, but ultimately decided the benefits did not outweigh the additional cost in power and die space for its design. Qualcomm is not divulging any lower-level details of its Kryo architecture, so we’ll have to see what, if anything, we can infer from our test data.

Qualcomm's Snapdragon 8xx Flagship Family


Snapdragon 820Snapdragon 810Snapdragon 805Snapdragon 801
Manufacturing Process14nm FinFET20nm HKMG28nm HPm28nm HPm
ArchitectureARMv8-A (32/64-bit)ARMv8-A (32/64-bit)ARMv7-A (32-bit)ARMv7-A (32-bit)
CPUQualcomm Kryo (2x @ 2.15GHz + 2x @ 1.59GHz)ARM Cortex-A57 (4x @ 2.0GHz) + ARM Cortex-A53 (4x @ 1.5GHz) [big.LITTLE]Qualcomm Krait 450 (4x @ 2.65GHz)Qualcomm Krait 400 (4x @ 2.45GHz)
GPUQualcomm Adreno 530 @ 624MHzQualcomm Adreno 430 @ 630MHzQualcomm Adreno 420 @ 600MHzQualcomm Adreno 330 @ 578MHz
Memory InterfaceLPDDR4-1866 2x 32-bit (29.9GBps)LPDDR4-1600 2x 32-bit (25.6GBps)LPDDR3-800 2x 64-bit (25.6GBps)LPDDR3-800/933 2x 32-bit (12.8/14.9GBps)
Camera ISP14-bit dual ISPs (1.5GP/s throughput, image sensors up to 2x 25MP)14-bit dual ISPs (1.2GP/s throughput, image sensors up to 55MP)12-bit dual ISPs (1.2GP/s throughput, image sensors up to 55MP)dual ISPs (930MP/s throughput, image sensors up to 21MP)
DSPHexagon 680 @ less than 1GHzHexagon V56 @ 800MHzHexagon V50 @ 800MHzHexagon V50 @ 800MHz
Integrated ModemX12, LTE Cat 12/13, up to 600 Mbps DL & 150 Mbps ULX10, LTE Cat 9, up to 450 MbpsMDM9x25, LTE Cat 4, up to 150 Mbps

While information about Kryo is scarce, details about Snapdragon 820’s Adreno 530 GPU is nonexistent. Beyond the name, the only thing we know for sure is that it runs at 133-624MHz. When pushed for more info, Qualcomm said it made lots of small architectural changes throughout the design, which would imply that the Adreno 530 is not a drastic redesign, but an evolution of the Adreno 430. One of the changes it mentioned was making better use of data compression when moving data around within the GPU in order to reduce power consumption.

Given Qualcomm’s focus on heterogeneous computing, it’s no surprise that the GPU and CPU can both snoop into the other’s cache, enabling better sharing of data, since both processors use 64-bit virtual addresses. With a heavy focus on compute capability, we also expect the Adreno 530 to further improve ALU performance, something which Qualcomm has done for the past several generations.

The Adreno 530 supports the latest graphics API standards, including OpenGL ES 3.1 + Android Extension Pack, DirectX 12, and Vulkan (once ratified by Khronos). Like the Adreno 430, the 530 includes a dedicated fixed-function block in hardware for accelerating tessellation.

The Snapdragon 820 comes with the brand-new Kryo CPU core, a new Adreno 530 GPU, as well as a new Image Signal Processor (Spectra ISP) and a Digital Signal Processor (Hexagon 680 DSP). Each of them come with significant boosts in performance over the previous generation, but they can also work together through heterogeneous computing to finish tasks more than twice as fast than if only the CPU was being used and save up to 40 percent energy.

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  • blackmagnum
    ...so, Apple's the Intel of the mobile cpu world, while Qualcomm's the AMD. One brings the performance while the other offers better value.
  • donjay
    No, Apple is not Intel of the CPU world.

    Apple is not actively sabotaging Android devices by offering subsidies to Android Tablet and Phone manufacturers.
  • megamanxtreme
    I really hope that the 820 is not as hot as the 810 gets, if not, I'll have to wait for the 830. I found the 950XL having to need a liquid cooler an insult.
    Until then, I'll survive with the 800 on my Lumia 1520.

    Actually, to blackmagnum, Qualcomm is being rumored to pay companies to include their processors, not sure if they are paying to exclude the competition, but it sounds similar to what Intel did to cut-off AMD on a lot.

    Found an article: http://www.zdnet.com/article/eu-to-qualcomm-youve-been-paying-to-shut-out-rival-chip-makers/
  • LordConrad
    Quote:
    No, Apple is not Intel of the CPU world. Apple is not actively sabotaging Android devices by offering subsidies to Android Tablet and Phone manufacturers.

    I believe he meant it in terms of performance.
  • nitrium
    Quote:
    No, Apple is not Intel of the CPU world. Apple is not actively sabotaging Android devices by offering subsidies to Android Tablet and Phone manufacturers.

    Apple also doesn't allow anyone other than Apple to use their CPU... exactly UNLIKE Intel, who lets anyone use their chips in any device you can dream up.
  • monsta
    look forward to seeing the 820 in the next flagship phones , if the numbers are correct on paper it's going to be a great chip
  • jasonelmore
    Apple's CPU Cores are clocked quite a bit higher than the 820 in these test.. Also the Adreno GPU is kicking apple's a9 butt.
  • ZolaIII
    Looks like S620 will be lovely.
    Actual splitting the Kryo cores in two clusters whose a dumb move.
    They will certainly get a performance edge in real usage where 2 cores are mostly sufficient enough (Web, apps) but in cases where you need more it will even be under the S620 so that's shooting in their own feat.
    I am not impressed with Spectra or QDSP but I am impressed with GPU performance.
    So in summary if they don't blow with GPU on S620 along with pricing they culd stay in the game as S620 could be a wonderful mainstream SoC all well balanced otherwise it will be a game over for them.
    I won't be crying for them as I didn't for Texas Instruments or Broadcom that they pushed out (that they will finally pay for) but truth is if they go down we are all without any open stock (I don't count Exunos as one more OEM ever used them).
  • wh3resmycar
    all those processing power for what? sending a d*ck pic in snapchat? smartphone performance has been so much saturated since the snapdragon s4. i'd take this 820 @ half the clocks plus 5000mah of battery in a smart phone because running your phone longer in the day makes more sense than any other gimmicks out there.
  • daniel_103
    147653 said:
    all those processing power for what? sending a d*ck pic in snapchat? smartphone performance has been so much saturated since the snapdragon s4. i'd take this 820 @ half the clocks plus 5000mah of battery in a smart phone because running your phone longer in the day makes more sense than any other gimmicks out there.


    So true! Is the first time when i read a good comment and a very real. This is a question that many people should think about... Are we use our smartphones for playing video games or for the real communications and network connection? What do people want from a smartphone? You expecting to run AutoCAD on your smartphone, or 2 days without recharge and full network?
  • Tahlula
    I am more excited about possibly being able to run apps such Cortana or Siri locally. Still dreaming of my own Jarvis (Iron Man reference). I refuse to knowingly allow Apple or Microsoft to listen to my conversations recorded on their servers as the apps are currently handled (the cloud). I'm fully aware there is no digital privacy but I'm going down kicking and screaming! LOL
  • Badelhas
    Battery life is much more important to me than those benchmarks.
  • bit_user
    I was initially disappointed, until I examined the single-core benchmarks. Still kinda sad they didn't dethrone Apple. Otherwise, looks promising.

    The core config strikes me as odd. big.LITTLE config makes more sense when the little cores are actually *little*. If the cores are going to be the same, then I think they should have just run all 4 cores at variable clock speed w/ the same ceiling (and globally limited by a power/thermal management scheme like Intel's Turbo Boost). Each core should have its own L2 cache and flush it when the core idles. Then, you could turn off that core's L2 and it burns virtually no power. The benefit would be better performance on tasks using > 2 cores. With those power savings in hand, they could afford more total L2 cache, to offset the reduction in available cache for the 1-2 core case.

    But I assume Qualcomm simulated many use cases and chose this one to balance performance, battery life, and cost.
  • bit_user
    Thanks for all the benchmarks, BTW. I've beeen waiting for this.
  • SBMfromLA
    Quote:
    Quote:
    No, Apple is not Intel of the CPU world. Apple is not actively sabotaging Android devices by offering subsidies to Android Tablet and Phone manufacturers.
    Apple also doesn't allow anyone other than Apple to use their CPU... exactly UNLIKE Intel, who lets anyone use their chips in any device you can dream up.


    No, but Intel does have a history of pressuring companies to only use their chips instead of including AMD's
  • bit_user
    2140403 said:
    I'm fully aware there is no digital privacy but I'm going down kicking and screaming! LOL
    Check out Silent Circle's BlackPhone series. Not quite the cheapest hardware, but you either pay with your privacy or your wallet. At least with the latter, you know the cost up front.
  • bit_user
    147653 said:
    all those processing power for what?
    They clearly have their eye on the growing AR & VR markets, as you can see from some of the marketing material on their website.

    Anyway, if you don't need the performance, nobody is forcing you to buy such a high-end SoC.
  • kvragec
    It seems to me that Qualcomm is aiming at sustained performance with little to almost no throthling. 4 cores on 14nm LPP process could end up really cool. Also, heterogenous computing can help at that. To me SD820 looks like a winner. Also, nothing stops them to launch SOC with 8 Kryo cores in the future.