It's more comparable to the sort of memory bus you'd typically see on a GPU... which is exactly what you'd hope for on a system with high-end integrated graphics. :)

You'd expect HBM or GDDR6 to be used. But this is seemingly LPDDR5 that's being used.

So its still quite unusual. Its like Apple decided to take commodity phone-RAM and just make many parallel channels of it... rather than using high-speed RAM to begin with.

HBM is specifically designed to be soldered near a CPU/GPU as well. For them to be soldering commodity LPDDR6 is kinda weird to me.

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We know it isn't HBM because HBM is 1024-bits at lower clock speeds. Apple is saying they have 512-bits across 8 channels (64-bits per channel), which is near LPDDR5 / DDR kind of numbers.

200GBps is within the realm of 1x HBM channel (1024-bit at low clock speeds), and 400GBps is 2x HBM channels (2048-bit bus at low clock speeds).

HBM isn't just "soldered near", it's connected through a silicon interposer rather than a PCB.

Also we know it's not HBM because the word "LPDDR5" was literally on the slides :)

> just make many parallel channels of it

isn't that just how LPDDR is in general? It has much narrower channels than DDR so you need much more of them?

> isn't that just how LPDDR is in general? It has much narrower channels than DDR so you need much more of them?

Well yeah. But 400GBps is equivalent to 16x DDR4 channels. Its an absurdly huge amount of bandwidth.