Qualcomm Snapdragon 820 Experience: HMP Kryo and Demosby Joshua Ho on November 10, 2015 5:20 PM EST
- Posted in
- Snapdragon 820
While the Snapdragon 820 has had a number of announcements about various aspects of the SoC, some details have been mostly left to the imagination. Today, Qualcomm held an event to release some details about Snapdragon 820, but also to show off what can be enabled by Snapdragon 820. Some of the main details released today include some estimates of power, and some additional disclosure on the Kryo CPU cores in Snapdragon 820.
In power, Qualcomm published a slide showing average power consumption using their own internal model for determining days of use. In their testing, it shows that Snapdragon 820 uses 30% less power for the same time of use. Of course, this needs to be taken with appropriate skepticism, but given the use of 14LPP it probably shouldn’t be a surprise that Snapdragon 820 improves significantly over past devices.
The other disclosures of note were primarily centered on the CPU and modem. On the modem side, Qualcomm is claiming 15% improvement in power efficiency which should eliminate any remaining gap between LTE and WiFi battery life.
On the CPU side, while the claims of either doubled performance or power efficiency have been discussed before, new details on the CPU include that the quad core CPU is best described as an HMP solution with two high-performance cores clocked at 2.2 GHz and two low-power cores clocked at 1.6 or 1.7GHz when looking at previous Qualcomm SoCs with two clusters that share an architecture. Qualcomm also disclosed that the CPU architectures of both clusters are identical, but with differences in cache configuration. However, the differences in cache configuration weren’t disclosed. I wasn't able to get an answer regarding whether this is an ARM big.LITTLE design that uses CCI-400 or CCI-500, but given that there's an L3 cache shared between clusters it's more likely that this is a completely custom HMP architecture.
In addition to these disclosures, we saw a number of demos. Probably the single most interesting demo shown was Sense ID, in which it was shown that fingerprint sensing worked properly through a sheet of glass and aluminum. To my recollection both the glass and aluminum were 0.4mm thick, so the system seems to be relatively robust. For those unfamiliar with Sense ID, rather than relying of high-resolution capacitive touch sensing the system uses ultrasonic sound waves to map the fingerprint, which allows it to penetrate materials like glass and metal and improves sensitivity despite contaminants like water and dirt.
One area of note was that Qualcomm is now offering their own speaker amp/protection IC that would compete with ICs like the NXP TFA9895 that are quite common in devices today. The WSA8815 chip would also be able to deliver stereo sound effects in devices with stereo front-facing speakers. It seems that the primary advantage of this solution is cost when bundled with the SoC, but it remains to be seen whether OEM adoption would be widespread.
One of the other demos was improved low light video and photos by using the Hexagon 680 DSP and Spectra 14-bit dual ISP. The main area of interest in this demo was improved visibility of underexposed areas by boosting shadow visibility, while also eliminating the resulting noise through temporal noise reduction.
On the RF side, in addition to showing that the Snapdragon 820 modem is capable of UE Category 12/13 LTE speeds Qualcomm also demonstrated that the Snapdragon 820 is capable of dynamically detecting WiFi signal quality based upon throughput and other metrics that affect VOIP quality and seamlessly handing off calls from WiFi to LTE and back. We also saw a demo for Qualcomm’s closed-loop antenna tuning system which allows for reduced impedance mismatch relative to previous open-loop antenna tuners which loaded various antenna profiles based upon things like touch sensing of certain critical areas.
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extide - Tuesday, November 10, 2015 - linkInteresting choice with the 2+2 CPU config. I'm excited for this chip!
DevilSlayerWizard - Tuesday, November 10, 2015 - linkOooohhh looks like someone followed up on the ideal configuration of 2 LP + 2 HP configuration...
jjj - Tuesday, November 10, 2015 - link2x efficiency would mean 2x perf at same power as S810 but they can't push it that far on the power side again. They compensate a bit for this with just 2 cores clocked high but , in the end, the 2x perf claim doesn't fit the math. So i guess maybe we get 25% over Exynos 7420. No benchmarks again so something is off there.
jjj - Thursday, November 12, 2015 - linkNew Geekbench high score for SD820 http://browser.primatelabs.com/geekbench3/compare/...
Doesn't look impressive vs A72 at 2.4-2.5Ghz in integer and FP if the score is close to what it will be in shipping products but not bad either.The memory score is very high, assuming 128 bit bus but remains to be seen what Mediatek does with the X30 on the memory side and ofc Exynos 8890.
The multi-core score better not be final, it would mean it gets rather hot pretty fast.
Speaking of the 8890, the 30% CPU perf gain claim might not be great but T880MP12 should beat SD820 easily.
colinisation - Tuesday, November 10, 2015 - linkInteresting to see someone else go the HMP route, I put this question to one of their peeps on twitter just yesterday.
Does the fact that an L3 is present preclude it from being based on ARM CCI-X00, I thought the CCI could utilise an L3$?
Andrei Frumusanu - Tuesday, November 10, 2015 - linkThere is no CCI with L3 so likely this is just a tightly coupled design with coherency being handled by the L3.
MrCommunistGen - Tuesday, November 10, 2015 - linkThat was my assumption as well. I like this idea and am curious to see what perf/latency and energy usage looks like switching from cluster to cluster on S820 compared to those that use big.LITTLE.
zeeBomb - Tuesday, November 10, 2015 - linkIts a return of the king: THE KING OF QUAD-CORE CHIPSETS!
skavi - Thursday, November 12, 2015 - linkHopefully the king of all ARM chips. I don't want another Exynos making custom OS's difficult on the S7.
StormyParis - Tuesday, November 10, 2015 - linkWhat ? No review ?