[wmf]

Apple does not have on-die RAM. The SoC is a normal logic die and the RAM is regular DRAM.

[samcheng]

Ah - I see, the DRAM is literally BGA'd right next to the die. So that $200 upcharge is mostly profit... Thank you!

[vbezhenar]

It's called "package on package". The RAM is different chip, however it's located very close to the CPU chip and both are under a single cover. The end result is a "package".

I think that GPUs use similar approach.

[RF_Savage]

AMD Vega used HBM next to the GPU die, but most GPU manufacturers are now back to discrete chips on the GPU circuit board.