Hacker News new | past | comments | ask | show | jobs | submit login

> Honestly I don't understand why there's not something like a 256 core ARM laptop

The high power ARM cores aren’t that small. If you took the M2 and scaled it up to 256 cores, it would be almost 7 square inches. You can’t just scale a chip like that, though, so the interconnects would consume a huge amount of space as well. It would also consume over 1000W.

The latest ARM chips are great, but some times I think the perception has shifted too far past the reality.




7 square inches would also include an enormous GPU and tons of accessories.

The actual cores are about .6/2.3 mm², and local interconnects and L2 roughly double that.

So with just those parts, 256 P-cores would be about 1.5 square inches, and 256 E-cores would be about half a square inch. And in practical terms you can fabricate a die that's a bit more than a square inch.

Of course it wouldn't use 1000 watts. When you light up that many cores at once you use them at lower power. And I doubt a 256 core design would have all that many P cores either.

As a rough estimate, you could take the 120mm² M1 chip, add 28 more P-cores with 110mm², 220 more E-cores with 300mm², 128 more MB of L3 cache with 60mm², 100mm² of miscellaneous interconnects, and still be on par with a high end GPU.

That sounds doable but is pushing it. A 128 core die, though, has nothing stopping it except market fit.


even a 128 core part made like that will perform pretty atrociously. scaling up the core count without scaling the cache count means you have a lot of cores waiting for memory. also when you have 128 cores, you almost certainly need more memory channels to have enough bandwidth.


I explicitly included more cache.

And the memory controllers aren't that big on the die. You could include a bunch more on a 128 core model.


Could we make the chips go slower like around 1Ghz? Maybe that is not feasible with the current software architecture to achieve great user experience.




Guidelines | FAQ | Lists | API | Security | Legal | Apply to YC | Contact

Search: