Thursday, September 16, 2021 [Tweets] [Favorites]

Performance of the A15

Jason Snell:

Here’s a funny thing about Tuesday’s announcement of the A15 Bionic: Apple didn’t compare its performance to the A14. In the past, Apple has compared the power of its iPhones to previous models. But this year, Apple has chosen to proclaim that the A15 in the iPhone 13 Pro has 50 percent better graphics and CPU performance “than the competition.”

Given that Apple has generally been ahead of its smartphone competition in terms of processor power, this suggests that the A15 shows less improvement over the A14 than it does over the Qualcomm processors in leading Android phones. And it makes me wonder if Apple is perhaps trying to soft-pedal a new chip that isn’t much faster than the older model.

Dylan Patel (tweet, via Meek Geek):

The CPU is claimed to be 50% faster than the competition while GPU is claimed to be 30% or 50% faster depending on whether it is 4 cores or 5 cores. They are sticking with a 16 core NPU which is now at 15.8 TOPs vs 11 TOPs for the A14. There is a new video encoder and decoder, we hope it incorporates AV1 support. The new ISP enables better photo and video algorithms. The Pro models have variable refresh rate, so that likely necessitated a new display engine. Lastly, the system cache has doubled to 32MB. This was likely done to feed the GPU and save on power. SemiAnalysis also believes Apple moved to LPDDR5 from LPDDR4X.

[…]

The most important thing to note is that the CPU gains are identical from the A12 to A14 as they are from A12 to A15. The GPU gains are quite impressive with a calculated 38.5% improvement. This is larger than the A13 and A14 improvements combined.

[…]

SemiAnalysis believes that the next generation core was delayed out of 2021 into 2022 due to CPU engineer resource problems. In 2019, Nuvia was founded and later acquired by Qualcomm for $1.4B. Apple’s Chief CPU Architect, Gerard Williams, as well as over a 100 other Apple engineers left to join this firm. More recently, SemiAnalysis broke the news about Rivos Inc, a new high performance RISC V startup which includes many senior Apple engineers. The brain drain continues and impacts will be more apparent as time moves on. As Apple once drained resources out of Intel and others through the industry, the reverse seems to be happening now.

Eric Slivka:

These scores represent a roughly 10% increase in single-core performance and 18% increase in multi-core performance compared to the A14 Bionic in the iPhone 12 lineup.

Jason Snell:

If accurate, this would place the A14 to A15 performance boost in line with recent updates. What makes this a question at all is that Apple hasn’t directly compared the two chips, instead opting to compare the iPhone to “the competition.”

Previously:

Update (2021-10-05): Ben Bajarin:

While it isn’t always obvious, Apple’s integrated product design approach of hardware, software, and silicon has led to many of the advances in camera, battery life, AI, video capture performance, and even ProMotion on iPhone 13 Pro. Apple has a luxury other silicon companies don’t. They custom-tune their architecture and silicon design specifically for iPhone and the feature they want iPhone to have. This allows them to spend their transistor budget on features instead of just pure performance.

[…]

While I will admit there is a small percentage of Apple customers who upgrade every year and a percentage more who upgrade every two years because they are on upgrade plans, the vast majority of consumers upgrade every 3-4 years. I thought it would be interesting to look at some basic iPhone benchmarks through the years and look at how much performance improvement happens every four years.

Andrei Frumusanu (Hacker News, MacRumors):

Compared to the A14, the new A15 increases the peak single-core frequency of the two-performance core cluster by 8%, now reaching up to 3240MHz compared to the 2998MHz of the previous generation. When both performance cores are active, their operating frequency actually goes up by 10%, both now running at an aggressive 3180MHz compared to the previous generation’s 2890MHz.

[…]

On the CPU side of things, Apple’s initial vague presentation of the new A15 improvements could either have resulted in disappointment, or simply a more hidden shift towards power efficiency rather than pure performance. In our extensive testing, we’re elated to see that it was actually mostly an efficiency focus this year, with the new performance cores showcasing adequate performance improvements, while at the same time reducing power consumption, as well as significantly improving energy efficiency.

The efficiency cores of the A15 have also seen massive gains, this time around with Apple mostly investing them back into performance, with the new cores showcasing +23-28% absolute performance improvements, something that isn’t easily identified by popular benchmarking. This large performance increase further helps the SoC improve energy efficiency, and our initial battery life figures of the new 13 series showcase that the chip has a very large part into the vastly longer longevity of the new devices.

1 Comment

> If accurate, this would place the A14 to A15 performance boost in line with recent updates.

Nah. From A10 to A14, single-threaded results in Geekbench went up 25.1%, 20.1%, 19.7%, and 19.4%. So there was a slight downward trajectory, but it still rounds to roughly 20%.

The A15 preliminary results suggest another 9.3%. That’s clearly an outlier. (Clock-by-clock, it seems the change is merely 2.5%, but that’s neither here nor there.)

I hope this is only a sign of “we’re taking an off year to focus on power efficiency and/or because we’re busy finalizing high-end Mac CPU features”.

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