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by _lbaq 2032 days ago
It’s also a 7nm design that has to deal with things like PCI busses, external memory on a narrower bus etc. so actually it do very well compared to the m1.

I’m interested to see how Apple can make this scale, can you get a Mx laptop with 64 Gb? Or will that has to be soc external memory for the process to scale?
2 comments
my123 2032 days ago
Apple chips have PCIe since forever too, in fact Wi-Fi + BT is plugged over PCIe on them. Thunderbolt with two 40Gb/sec links isn't tiny either.

64GB will come for future laptops. And Apple can scale with a single package beyond 64GB too, very high performance solutions included. See the A100 80GB from NVIDIA with 2TB/sec of memory bandwidth, with RAM as part of the package, just not in the same die.

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kllrnohj 2032 days ago
> Thunderbolt with two 40Gb/sec links isn't tiny either

It comparatively is. Thunderbolt is basically a PCI-E Gen 3 x4 slot but over a (very) short cable. Commonly more like an x2 link since getting the x4 speeds is difficult. Commonly 2 thunderbolt ports also share a single controller, so it's a 40Gb/sec combined maximum not per-port (either port can saturate, but you can't hit 80Gb/s total). It's unclear what the M1's controller actually is here, if it's dedicated lanes per port or just bifurcation.

But lets say the M1 is full on 2 TB3 controllers, for a combined 80Gb/s over those 2 ports. That's still not much. By comparison the 5600x has 24 PCIe Gen 4 lanes on it. That's 380 Gb/s of bandwidth off of the CPU. These are all things Apple would need to heavily beef up when they make the Apple Silicon variants of the larger class products. You can't do a Mac Pro replacement with 80 Gb/s of I/O. That'd be a joke. Apple obviously will scale up the I/O, but that costs power, too. It won't be free.

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my123 2032 days ago
That I/O is relatively inexpensive power-wise from experience, and is totally off when unused.

For those Ryzen parts, the thing that hikes power use a lot is having a separate northbridge in the same package instead of an SoC, with the vast majority of that additional power use being due to that.

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gsnedders 2032 days ago
> I’m interested to see how Apple can make this scale, can you get a Mx laptop with 64 Gb? Or will that has to be soc external memory for the process to scale?

Memory is already external to the SoC on the M1; it's on the same package but it's not a single chip.

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