2015, however, brought fresh headwinds. The Snapdragon 810 was widely believed to have an overheating problem. The actual situation was more complex than that; at least some Snapdragon 810 devices weren’t profiled properly and didn’t manage their own thermals well as a result. Later point iterations on the chip may also have improved the situation. Either way, Qualcomm took a serious revenue hit when Samsung opted to use its own silicon in the Galaxy S6 family, even overall Galaxy sales failed to meet expectations.
All of which is to say, Qualcomm needs this chip to be a hit. The “Kryo” CPU core is a custom chip built on Samsung’s second-generation 14nm technology (14 LPP). Qualcomm is advertising the CPU as offering up to 2x performance and 2x efficiency compared to previous generation parts, which is rather frustratingly vague. At a guess, this refers to the chip’s theoretical maximum burst performance for a very short period of time and its overall efficiency when measured at idle, or under specific workloads. Intel, AMD, and other vendors excel at this kind of particular argument — actual power consumption improvements and performance boosts tend to be highly workload dependent. Qualcomm is encouraging the use of its DSP and GPU as computation offloads to improve overall CPU efficiency.
Qualcomm does offer some additional color around overall power consumption, though they don’t disclose their test environments or conditions.
While we don’t know the criteria that Qualcomm used to arrive at these conclusions, the 65% of Snapdragon 801 power metric makes sense given what we know about estimated improvements for 14nm compared to TSMC’s 28nm planar silicon. It’s still sobering to note that this improvement arrives roughly three years since Qualcomm announced the Snapdragon S4 family, which featured the then-new custom Krait CPU core. Even if we take Qualcomm at its word about the relative level of advancement in CPU performance and power consumption, it’s taken three years and two node shrinks to deliver the kind of improvements we used to see in 18 months and a single node shrink — and as we’ve already noted, we fully expect that Qualcomm’s improvement claims will be situational, just as AMD’s and Intel’s are. “Real-life” workloads simply vary too much to be easily captured in a single metric.
Qualcomm’s Tim McDonough took to Twitter to answer questions about the new chip, but he kept his answers light. Qualcomm claims more than 60 device wins for the new 820 SOC, including cameras, cars, and drones. Nvidia has been the SoC manufacturer making noise about the automotive business of late, so this could imply that QC wants to challenge NV on turf Team Green is hoping to stake out for itself.
Without much concrete detail on Kryo, we’re forced to make some educated guesses about the core. Qualcomm has already revealed that the chip is targeting a 2.2GHz clock frequency. The Exynos 7420, built on Samsung’s 14nm LPE process, uses a 1.5GHz frequency base and a 2.1GHz boost clock. What’s interesting to me is that Qualcomm has walked back the 810’s commitment to a big.Little approach and instead opted for a single unified processor block. This suggests that the Kryo CPU may emphasize instructions-per-cycle efficiency over clock speed.
Our guess is that Qualcomm has staked out a midpoint between Apple’s A9 processor, which tends to pound the rest of the ARM family when it comes to single-thread performance, and scaling up to 8 or more cores, the way Samsung and companies like MediaTek plan to do. A higher-efficiency quad-core may represent the sweet spot between these two extremes. Presumably, Qualcomm is using DVFS to control its clock frequencies and power gating, though there’s always an outside chance that it adopted a technique like the AVFS AMD is using for Carrizo.
Putting it all together
Qualcomm’s comprehensive spec sheet on the Snapdragon 820 is shown below. The company is claiming a bevy of improvements for its Adreno 530 GPU (up to 40% more performance and 40% greater power efficiency than previous-generation hardware), new hardware decode and encode engines, an X12-class modem, and a variety of enhancements to image processing and security.
We’ve also heard tell that while Qualcomm’s SoC design for its upcoming server family is quite different from Snapdragon 820, the CPU may derive from Kryo. This makes sense, if true — building a common architecture and leveraging it across multiple contexts is how both AMD and Intel have historically done things, to good effect (Bulldozer notwithstanding). If Qualcomm is serious about competing in the server market, it will want to leverage economies of scale.
If the Snapdragon 820 does well, we’ll see that reflected in phone design wins at CES and Mobile World Congress in early 2016. The Snapdragon 810 may not have won the accolades that the Snapdragon 800 family received, but the 808 and 810 combined have sold well and shipped in a number of high-profile designs. At the same time, however, Qualcomm faces increased competition from mainland Chinese and lower-cost Taiwanese companies. It needs the Snapdragon 820 to sell well if it wants to retain its de facto leadership of the Android market — a position Samsung arguably usurped with its own Exynos 7420 in 2015.
Devices based on the Snapdragon 820 are expected to ship in the first half of next year, probably starting in March or April.