At CES 2017 Qualcomm officially introduces its new Snapdragon 835 SoC (processor) which will surely power a large number of high-end smartphones. We knew that it was coming, and this is now real. While the Snapdragon 821 was a “performance kicker” of the Snapdragon 820 chip, the Snapdragon 835 processor is built on the latest 10nm Samsung semiconductor manufacturing process, which is the second generation FINFET (3D) transistors for this category of products.
Despite having a record 3 Billion transistors, Snapdragon 835 has a smaller die size and a smaller packaging as its predecessor. As always with the semiconductor business, you either increase the performance and functionality, or you see the price of your product plunge because of manufacturing progress. Fortunately for Qualcomm, the demand for mobile computing is simply relentless, so Moore’s law is a friend. The good news is that the leaked Snapdragon 835 specifications, including from benchmarking tools, were largely true.
~20%-25% performance improvement
Kyro CPU Cores
The most measurable elements of such a processors are the CPU (main clusters of general-purpose units) and the GPU (graphics units). This is because there are well-established benchmarks, with known workloads that can be tested from generation to generation.
There are no independently confirmed benchmarks at the moment, but Qualcomm claims that the “Performance Cluster” which is a group of four fast CPUs (2.45GHz, 2MB cache) can generate a ~20% performance improvement over the last generation. At the same time, it’s good to remember that this cluster is used only for peak performance activities.
There’s another 4-core CPU cluster (1.8GHz, 1MB cache) which is the “Efficiency Cluster” which are optimized for power efficiency (frequency/voltage), and that 80% of all CPU activity happens there, according to Qualcomm’s analysis.
Both clusters are based on the Qualcomm Kyro 280 CPU core design, which is “semi-custom” (the Kyro in Snapdragon 821 was “fully custom”) and based on ARM’s Cortex design. How much was customized and what remains unclear for now as Qualcomm didn’t (yet) go into those details. The important piece of information is that Kyro is designed to offer both extreme performance, and extreme power efficiency – to an extent unseen in previous generations.
Between the architectural changes and the better semiconductor process, Qualcomm says that overall, Snapdragon 835 is 50% more power-efficient (as Snapdragon 821). This is a huge number.
Adreno 540 GPU
On the graphics size, performance should be up by 25% according to Qualcomm’s estimation, which is probably based on what it considers to be representative or important application types. Typically, gaming or VR would be the main consumer for this kind of graphics performance. However, it is important to remember that a GPU also includes 2D video stream processing units that are used for movie processing, and potentially for GPU-based general purpose computations. For PC users to relate, Adreno 540 is a DirectX 12 capable GPU design.
Adreno 540 also supports HDR10, which is a standard for the next-generation video content with High Dynamic Range (HDR). 10-bit colors also mean that color accuracy will explode (60X more) and push display technologies to their limits. Snapdragon 835 devices should also be “UltraHD Premium Ready”, which is a TV/Video standard backed by large companies that define: resolution, color depth, color accuracy and brightness levels for the whole content chain.
For gamers, the more interesting feature is QSync. Not to be confused with QNap’s Qsync, which is a networking feature, Qualcomm’s QSync is a technology similar to NVIDIA G-Sync and AMD’s FreeSync in the sense that it control the refresh rate of the display to match the current (and changing) rendering display. The benefit of such technologies is that the average framerate is up, and there is never any visible tearing/stuttering on the screen. The application feels smoother, as of you were at 60FPS at all times.
Hexagon DSP power
Snapdragon chips always come with an integrated DSP or Digital Signal Processor. Qualcomm’s is called Hexagon. These type of processors are designed to perform computation on large quantities of data, whether it is a huge dataset or a continuous stream, they are just really good at performing computing tasks at power-levels so low that CPU cores cannot match them.
DSPs are also much more obscure to test and benchmark because they are not directly exposed to the Operating System, which means that benchmark developers have a hard time to write tests. Because of this abstraction from the OS, there is often no API to talk to the DSP directly.
Instead, most developers will use the DSP indirectly by integrating vendor-specific libraries for VR/AR/Audio, etc… in fact, developers don’t always know which compute unit (DSP, GPU, CPU) will be used, and it’s up to the chip maker’s library to decide. For example, Qualcomm uses the DSP to perform the VR head-tracking computations, in devices like the Snapdragon 820 VR.
That said, DSP do wield enormous computing power, especially if you look at them from a Performance/Watt perspective. In many cases, they are more convenient to use than GPUs which tend to be massive blocks of silicon which require equally massive amounts of data to process before it’s “worth” waking up and firing up possibly billions of transistors. DSP are more nimble and have an extremely important but often less glamorous role in a mobile computing platform.
With the rise of deep learning, Qualcomm made the Snapdragon 835 Hexagon compatible with TensorFlow (AI library) and Halide (image processing language), two popular platform/tools for high-performance computing and Artificial Intelligence (AI). Qualcomm estimates that the DSP is 25X more efficient in these use cases than CPU cores.
Spectra 180 ISP (Image Signal Processor)
The ISP is a specialized unit that is normally used to process data coming from the camera image sensor. Because of this specialization, it can process data at extremely high speed, at power levels simply not possible with any other computing units. Many SoC now have more than one ISP because devices have multiple cameras that can be used at the same time.
X16 LTE Modem
Snapdragon 835 will embed a Qualcomm X16 Modem, which supports LTE Advanced Pro, and is Qualcomm’s first Gigabit-class LTE modem. Announced in February 2016, this should be its first integration into a Qualcomm SoC. Qualcomm is also developing 5G Modems such as the Qualcomm X50 Modem, but these won’t be integrated for now and will start out as standalone chip/devices.
The continuous rise in wireless broadband performance is important because the size of digital content continues to grow. It is also important to consider that faster communications also mean that modems potentially stay ON for shorter periods of time, thus minimizing their power usage. The phones’ radios are one of the top two power consumers, along with the display.
As Virtual Reality (VR) and Augmented Reality (AR) take hold in compelling apps, the importance of 3D surround sound becomes critical for a proper immersion. Because of their interactive nature, it is impossible to predict where the user will be in the virtual environment. Therefore, it is necessary to have the ability to “render” sounds, instead of “playing back” sound.
The best analogy I can think of is to compare sound playback to a photo or a movie shot from a specific location. You can only see it from that location. If you have a 3D world similar to modern games like Call of Duty, you can effectively “render” the scene from anywhere. The same is true for audio, except that having a hyper-realistic “sound rendering” is much more attainable than having a hyper-realistic graphics rendering.
Technologies such as Dolby Atmos have achieved this for theaters and living rooms. Qualcomm can do something similar on mobiles, thanks to the use of sound objects and scenes.
Quick Charge 4.0 support
Snapdragon 835 will also support QuickCharge 4.0 which was announced on November 17. Everybody loves fast-charging, and this is arguably even more important than sheer battery capacity sometimes. In any case, charging speed is evolving faster than battery capacity, so ideally, we want both – and more of it.
Quick Charge 4.0 is 20% faster than the 3.0 version, and 2.5X faster than Quick Charge 1.0. Here is a complete overview of Qualcomm’s Quick Charge. We have yet to measure this in the real world, but we will know as soon as the first Snapdragon 835 phones arrive. In the meantime, the fastest charging phone we’ve ever seen is the Huawei Mate 9, which can charge at the astonishing speed of 80 mAh/mn, while Quick Charge 3.0 phones topped 54 mAh/mn in the best case (see our LG G5 review).
Quick Charge 4.0 is also more power-efficient, which means that less energy is lost during charge. This is important because lost energy tends to become heat, and heat slows down the charging process.
Qualcomm’s Snapdragon 835 is looking like an excellent system-on-chip, and we expect this sentiment to be confirmed by the arrival of the first hardware that can be looked at and reviewed independently. In the past, Qualcomm’s performance predictions have been accurate enough to be trusted, and the paper-specification seem to validate the performance claims. It’s going to be interesting to see what the competition from Samsung Semiconductors and HiSilicon (Huawei) will oppose in this market segment, but so far, Snapdragon 835 takes the pole position in the 2017 race.