The Snapdragon 8 Gen 1 Performance Preview: Sizing Up Cortex-X2
by Dr. Ian Cutress on December 14, 2021 8:00 AM ESTConclusionary Remarks: Arm v9 for Android
When we move through significant revisions of Arm’s architecture, up to v8 and now v9, it’s important to note that the new features defined in the ISA do not always fundamentally improve performance – it’s up to the microarchitecture teams to build the cores to the ISA specifications, and the implementation teams to enable the core in silicon with frequency and power efficiency. Accomplishing that requires a good process node, design technology co-optimization, and then partners that can execute by building the best devices for that processor.
Qualcomm’s target with the Snapdragon 8 Gen 1 is very clearly the 2022 Android Flagship smartphones. New cores, new graphics, enhanced machine learning capabilities, a step function in camera processing power, an integrated X65 modem, all built on Samsung’s 4nm process node technology. The flagship Android space is an area in which Qualcomm has been comfortable for a number of years, however the increased thermals of last generation’s Snapdragon S888 gave a number of analysts in the space a bit of a squeaky bum moment.
It’s hard to tell immediately in our small test if that still remains the case. Samsung’s 4nm node has improvements beyond the previous generation 5nm design, however Qualcomm’s presentational numbers were above and beyond those that Samsung provided, perhaps indicating that additional improvements both in architecture and implementation have led to those performance numbers.
Our testing shows +19% floating point performance on the X2 core, which is almost the +20% that Qualcomm quotes, but only +8% in integer, which is often the most quoted. We’re seeing power efficiency improvements for sure on the X2 core, with an overall efficiency improvement of 17%, but peak power has also increased, in part because some of our tests make use of the additional cache in the system. Our machine learning tests are +75% over the previous generation, although not the 4x numbers that Qualcomm states – we need to do more work here on power efficiency testing however. On the gaming side, our 'first run' numbers showcase some explosive gains in GPU throughput.
Although we’ve only done a few tests here, I would be remiss if I didn’t mention the elephant in the room: MediaTek. In the last month MediaTek announced a return to the high-end with a flagship processor of its own, using the same 1+3+4 configuration with slightly higher frequencies, more cache, and built on TSMC’s N4 process. Implementation here will be the key metric I feel, so how MediaTek has been able to optimize for TSMC N4 vs Qualcomm on Samsung 4nm is going to be analyzed. I should point out here that a processor is more than just the CPU cores, as we’ll see Adreno vs Mali on graphics, the different machine learning approaches, but also how the two companies approach 5G and connectivity, which has been one of Qualcomm’s most prominent strengths to date.
We look forward to testing the Qualcomm S8g1 in more detail in the New Year, as well as how many of the main smartphone OEMs choose Qualcomm for their flagship devices.
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Alistair - Tuesday, December 14, 2021 - link
Their GPU is great, their CPU is 3 years behind now, and this improvement over last year is almost nill. Sigh. Sad.Raqia - Tuesday, December 14, 2021 - link
I'm looking forward to the '23 Nuvia designed cores for laptop compute, so let's see what they can do.However, I think it's perfectly fine if they went with a smaller ARM solution for future phone SoCs: in the SG81 and the 888 they consciously chose to limit L3 cache sizes in their CPU complex (and hence single threaded performance) for 2 generations from the biggest possible to dedicate die area and power consumption for other higher impact purposes. To me, an ideal Apple phone would have 6 of their small cores so they can dedicate more die area to their GPU, NPU and ISPs.
John Carmack himself thought it best to throttle the CPU to half of maximum clock speed in even the XR2 (which is a 865 derivative using a faster clocked, bigger cache A77 as its biggest core):
https://twitter.com/ID_AA_Carmack/status/130662113...
https://twitter.com/ID_AA_Carmack/status/131878675...
but he praised the XR2 in no uncertain terms, calling it "a lot of processing"
https://youtu.be/sXmY26pOE-Y?t=1972
It is indeed the DSPs and the GPUs doing the heavy lifting in the VR use case; I don't see it being much different for phones where wireless data rates are by far the biggest bottleneck.
The CPU benches you see headlining many web SoC reviews matter only for the benchmark obsessed, but pretty much no one else.
Alistair - Tuesday, December 14, 2021 - link
Your throttling argument doesn't make sense when the iPhone is more efficient also. You can run an iPhone at Snapdragon speed, and then you use way less power.Raqia - Tuesday, December 14, 2021 - link
If you look at the efficiency curves for the A77 and the A13's big CPU, they're pretty danged close:https://miro.medium.com/max/1155/1*U7qA0vDhixGAYes...
The bigger point is, for phones it's well past the point of diminishing returns to pin the A13 CPU where most benchmarks do since it's simply not a bottleneck in realistic workloads. You can make a very fast CPU for bench-marketing purposes and get semi-technical people excited about your SoC, but you won't need to go very far along the curve to both hit its "knee" and have excellent performance.
Apple made the core for laptops and desktops (for which it's well suited) but included it in its iPhone for marketing purposes rather than to address actual performance needs. Some cite the fact that more apps are coded in Javascript and websites are more Javascript intensive these days, but by far the bigger culprit in responsiveness is data connectivity and they were happy to use Intel's inferior modems behind the scenes while trotting out big but irrelevant Geekbench scores. Furthermore, part of their battery-gate issue stems from the huge possible current draw of their CPUs, which while efficient still use high peak power and current.
Qualcomm has certainly been worse in efficiency and performance across multiple SoC processing blocks for the past two generations due to switching to Samsung as its premium SoC fab, and I certainly have no kind words for them in making that decision. However, given what they had to work with in terms of die area and power draw, they did make the correct decision in de-emphasizing the CPU block for relatively more grunt in the other blocks.
ChrisGX - Thursday, December 16, 2021 - link
Yes, that's right, but Samsung's inadequate process nodes are primarily responsible for Snapdragon parts (and all premium mobile SoCs based on licensed ARM IP) falling further behind. (Note: ARM SoCs are still seeing notable improvements in the execution rate of floating point workloads even as integer performance wallows.) For that reason, it will be very interesting to see how the TSMC fabbed MediaTek Dimensity 9000 acquits itself.The more telling part of this story, I think, is the failure of ARM and ARM licensees to manage this transition to high performance mobile SoCs while maintaining energy efficiency leadership. In the mobile phone world, today, Apple not only wears the performance crown but the energy efficiency crown as well.
Wilco1 - Saturday, December 18, 2021 - link
There are claims that Dimensity 9000 has ~49% better perf/W than SD8gen1: https://www.breakinglatest.news/business/tsmcs-4nm...That means the efficiency gap was indeed due to process as suspected. There is definitely an advantage in using the most advanced process 1 year before everyone else.
Raqia - Saturday, December 18, 2021 - link
Really good to see them pick up their game: bigger L3 cache and faster clocked middle cores seem to be part of the reason efficiency and multicore performance are up as well aside from process.Some rumors indicate the dual sourced version of the S8G1 (SM8475) may be more efficient than the samsung node fabbed version but not as much as expected. It seems like Qualcomm picks different sub-blocks to optimize with each generation: this gen it was most certainly the GPU. Looks like the CPU block can be expected to languish until they bring up the NUVIA designed cores likely in '24. As their initial focus was servers, NUVIA may not have had a suitable small core in the pipeline for '23 which is much more important for mobile than laptop scale devices.
Wilco1 - Sunday, December 19, 2021 - link
Yes it looks like Mediatek have done a great job. The larger caches should help power efficiency as well indeed. It will be interesting to see how the larger L3 and system cache compare with the Snapdragon and Exynos in AnandTech's benchmarks.Kamen Rider Blade - Tuesday, December 14, 2021 - link
I wonder how much more performance Android would gain by going with C++ instead of Java.https://benchmarksgame-team.pages.debian.net/bench...
There's ALOT of performance to be gained by going with C/C++/Rust.
The fact that Android went with Java for it's primary programming language while Apple went with a C/C++ derivative could be what explains the large gap.
jospoortvliet - Wednesday, December 15, 2021 - link
Might make a difference in day to day use but not in these benchmarks as they already use native code.