[bichiliad]

I think this kinda makes sense to me — the M1 Max has the same cores as the M1, just more of them and more of the performant ones, if I understand it right. The fastest work on the fastest core, when only working on a single core, is probably very similar.

[klelatti]

Maybe a little surprised - presumably the thermal limitations on a 16 inch laptop are potentially less limiting than on a 13 inch one so that single core could be pushed to a higher frequency?

[hajile]

M1 uses TSMC high-density rather than high-performance. They get 40-60% better transistor density and less leakage (power consumption) at the expense of lower clockspeeds.

Also, a core is not necessarily just limited by power. There are often other considerations like pipeline length that affect final target clocks.

The fact is that at 3.2GHz, the M1 is very close to a 5800X in single-core performance. When that 5800X cranks up 8 cores, it dramatically slows down the clocks. Meanwhile the M1 should keep its max clockspeeds without any issue.

We know this because you can keep the 8 core M1 at max clocks for TEN MINUTES on passive cooling in the Macbook air (you can keep max clocks indefinitely if you apply a little thermal pad on the inside of the case).

[kllrnohj]

> When that 5800X cranks up 8 cores, it dramatically slows down the clocks

Not that dramatic, it drops from ~4.8ghz to ~4.4ghz: https://www.anandtech.com/show/16214/amd-zen-3-ryzen-deep-di...

Actual drop varying depending on actual power consumption & temperature as Ryzen is more or less an entirely reactive system.

[klelatti]

Thanks - some very good points. Presumably this opens the possibility of higher single core performance on a future desktop design unless limited by pipeline length etc?

[runeks]

> We know this because you can keep the 8 core M1 at max clocks for TEN MINUTES on passive cooling in the Macbook air (you can keep max clocks indefinitely if you apply a little thermal pad on the inside of the case).

Is there a guide on how to apply this thermal pad?

I would love for my Air to not downclock.

Also why on earth does this thermal pad not come factory installed?

[qubitcoder]

That’s why the MacBook Pro M1 has fans. It’s designed for harder workloads where you’re maxing out the cores (multi-core compilation, video encoding, etc) for extended periods. This was well-documented and discussed previously. The tradeoff is increased heat, power consumption, and fan noise.

Realistically, those aren’t typical workloads for most people, especially for 10+ minutes (and especially on an ultralight and portable laptop). So I wouldn’t lose sleep over thermal pads.

[klelatti]

Maybe this is a reflection of the 16 inches higher thermal envelope?

https://www.macrumors.com/2021/10/21/new-macbook-pros-high-p...

[O_H_E]

> M1 uses TSMC high-density rather than high-performance.

Is that an actual product differentiation from TSMC? Or just observational + the fact that it's 5nm.

I'm actually curious from a chip manufacturing standpoint.

[hajile]

There’s actually three major version on N3 (sorry, I don’t have time to look up the similar articles on N5/7, but I think wikichip has a couple).

https://www.techdesignforums.com/blog/2021/06/03/three-libra...

I remember seeing a picture of a partner list for a TSMC node with a couple dozen libraries that not only changed based on density, but also on type of chip being built.

[floatingatoll]

Does the core speed of an M1 core change at all? I thought they used the low/high power cores at fixed-limit clock speeds.

It sounds crazy to consider, but maybe they’d rather not try to speed up the individual cores in M1 Max, so that they can keep their overhead competitively low. That certainly would simplify manufacturing and QA; removing an entire vector (clock speed) from the binning process makes pipelines and platforms easier to maintain.

[tedunangst]

For how long? Longer than it takes to run the benchmark?

[icosahedron]

I thought I remembered that in the presentation they had souped up the individual cores too. Must be I'm misremembering.

[sliken]

They didn't. However the cores enjoy more main memory bandwidth.