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by GeekyBear 1477 days ago
From Anandtech's deep dive into the performance and efficiency cores in the A15, which are reused here in the M2.

Performance Cores:

>Apple A15 performance cores are extremely impressive here – usually increases in performance always come with some sort of deficit in efficiency, or at least flat efficiency. Apple here instead has managed to reduce power whilst increasing performance, meaning energy efficiency is improved by 17% on the peak performance states versus the A14. If we had been able to measure both SoCs at the same performance level, this efficiency advantage of the A15 would grow even larger. In our initial coverage of Apple’s announcement, we theorised that the company might possibly invested into energy efficiency rather than performance increases this year, and I’m glad to see that seemingly this is exactly what has happened, explaining some of the more conservative (at least for Apple) performance improvements.

Efficiency Cores:

>The A15’s efficiency cores are also massively impressive – at peak performance, efficiency is flat, but they’re also +28% faster.

The comparison against the little Cortex-A55 cores is more absurd though, as the A15’s E-core is 3.5x faster on average, yet only consuming 32% more power, so energy efficiency is 60% better.

Conclusions:

>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.

https://www.anandtech.com/show/16983/the-apple-a15-soc-perfo...

1 comments

This is a really great article from Anandtech with benchmarks and analysis, it explained a lot of things.

> The overall performance gains are quite disappointing when you factor in the raw cost increase that comes with this new M2 and the fact that it has been nearly 2 years since the M1’s introduction.

Also the logic of article in the title is little weird to me. M1 was introduced in the same year as A14, they use the same core; while M2 uses the same core as A15, which introduced 1 year after M1. So technically M2 increased the performance by 18% in one year, not two years.

Though I'm curious why Apple didn't use A16's core in M2.

> Though I'm curious why Apple didn't use A16's core in M2.

Probably the smaller process node. There's low capacity and low yields for the first year or two of the smaller node. It might not be an issue for the base-level M2s, but they'll be expected to update the Pro/Max/Ultra line up as well in the next 8 months which have much larger die sizes and they'd end up throwing away most of the wafer.

Phones are the flagship product. They will always get the latest and greatest first, including cores, die shrinks, etc etc.
Which is weird because most iPhone users use all the power for stuff like WhatsApp. iPhones are plenty fast already (honestly probably mostly due to a well cared-for UI).
I assume Apple wants the phones to have the most efficient CPUs, since battery life is much more critical than laptops & desktops.
It’s my opinion that Apple sees putting the best processors in iPhones as being able to extend the life of the product. With that available compute overhead today it will feel “faster” longer and can take advantage of software features they develop 1-3 years down the line.
Power efficiency is more important in phones.
It is looking like A16 will be on a smaller node. Likely manufacturing it on the current node would be too expensive due to increased transistor count.

Available volume on the new node will be much smaller, so they had to prioritize. This is likely why only the iPhone pro will get the A16.

>Though I'm curious why Apple didn't use A16's core in M2.

We will know soon enough. My guess is that A16 is designed with TSMC 3nm in mind, that is why ( rumour ) only the new iPhone Pro will get A16, and iPhone 14 will stick to A15.

Given that M2 is available in a week or two, and the A16 isn't, I would say it's a scheduling thing. In order to have the M1 to M2 cadence not blow out, they have to make decisions about what can go into the product.
M1 2020, M2 2022?