It's not in the package? TIL... My misunderstanding seems to be common across the interwebs.

I remember Apple used to show slides depicting the M1 SoC as one unit containing a CPU, GPU, Neural Engine, cache, and DRAM all together. But slides shown at an Apple event definitely qualify for artistic license.

The memory is soldered on top of the package, here's an actual real life photo of the M1 package with two LPDDR packages sitting on it:

https://en.wikipedia.org/wiki/Apple_M1#/media/File:Mac_Mini_...

You could call that on-package, but it's not on-package in the same way that GPU HBM is, with that the main die and memory dies are packaged together on the same substrate. That's a much more difficult and expensive process, apparently packaging is the main bottleneck for H100/H200 production.

https://i.imgur.com/hFTPyjk.jpeg

For that H100 image, how do they get the top surface of all the chips on the same plane? Do they solder them "upside down", so the chips are sitting on a reference plane, and the PCB is allowed to "float"? Or is the soldering controlled enough that they can just heat and be done?

Nor is it a chiplet, in which case it would qualify as "in-SoC".

Wait till you learn that unified memory was in common use by pc's long before Apple "invented" it.

The statement is correct; it's not on the substrate similar to AMD's 3D cache or it doesn't use interposer like HBM.

You can consider it like a small PCB that has the CPU die and the memory soldered very closely nearby (and like mentioned +memory channels)