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> But I don't think there's much argument to be had here that the M1/M2 Apple cores are just bigger > You pretty much can make 2 cores fit inside of the M1 cor
by brigade 4y ago
> But I don't think there's much argument to be had here that the M1/M2 Apple cores are just bigger
> You pretty much can make 2 cores fit inside of the M1 core
My entire point has simply been debunking this. I'm pointing out that Apple, Intel, and AMD have similarly large area budgets for their big cores. Like, looking at actual chips produced on the same TSMC processes, you cannot fit two Zen4 cores inside of the space taken by one M1 or M2 P-core. You cannot fit two Zen2 or Zen3 cores within the space taken by one A12Z P-core. All of them have a somewhat similar per-core area budget, with difference in L2/LLC cache tradeoffs being the biggest differentiator in area.
And yes, even outside of cache they make different tradeoffs with what they spend the area on. Zen4 spends area on 512b registers and 256b ALUs, and clocking past 5GHz. Apple spends it on scalar resources and deep reordering. I'm not arguing that one tradeoff is universally better than the other, just that they end up similarly big.
Since you brought up cache throughput, Zen4 does 32B/cycle between L1 and L2 [1]. Anandtech measured M1's L2 cache throughput at about 440 GB/s across the 4 P-cores [2], which works out to 34B/cycle/core. Which sure sounds like the same per-core throughput to me.
> You can just... look at the damn die shot
I... did? That's how I estimated L2 cache and tags at 28% of Zen4's 3.84mm^2. Do you believe that that is incorrect, or that the M1 and M2 P-core areas of 2.281-2.756 mm^2 quoted by Semianalysis are incorrect?
[1] https://chipsandcheese.com/2022/11/08/amds-zen-4-part-2-memory-subsystem-and-conclusion/ https://chipsandcheese.com/2022/11/08/amds-zen-4-part-2-memo...
[2] https://www.anandtech.com/show/17024/apple-m1-max-performance-review/2 https://www.anandtech.com/show/17024/apple-m1-max-performanc...