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I'm very curious about the chips with external memory and how they'll do WRT performance in the high-end. Do we have a measurement of how much M1 spends waiting for memory after an L3 miss?

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The memory that the M1 uses is quite fast for LPDDR4X, but there's nothing _that_ special about it. Moving it off-package shouldn't have a significant impact.

True. Two LPDDR4X channels (at ~35GBps) would give the M1's ~70GBps memory bandwidth. I wonder if the tight packaging allows it to play with latencies being shorter.

The M1 just uses on-package memory, it’s nothing really special, it only avoids routing through the motherboard (which is convenient): instead if soldering the ram next to the SOC, it’s soldered onto the SOC.

It may have electrical benefits too - the capacitance of the line will likely be lower, and possibly the drive-strength might be lower. Both of those might figure into the power management of the chip...

But overall, yeah, it's not as though the RAM is part of the chip, it's just part of the package. Not a lot to see here.

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