The M1 Max/Ultra is already extremely dense design for that approach, it's really almost as dense as you can make it. There's packages stacked on top, and around, etc. I guess you could put more memory on the backside but that's not going to do more than double it, assuming it even has the pinout for that (let's say you could run it in clamshell mode like GDDR, no idea if that's actually possible, but just hypothetically).

The thing is they're at 128GB which is way way far from 1.5TB. You're not going to find a way to get 12x the memory while still doing the embedded memory packages.

Maybe I'll be pleasantly surprised but it seems like they're either going to switch to (R/LR)DIMMs for the Mac Pro or else it's going to be a "down" generation. And to be fair that's fine, they'll be making Intel Mac Pros for a while longer (just like with the other product segments), they don't have to have every single metric be better, they can put out something that only does 256GB or 512GB or whatever and that would be fine for a lot of people.

> You're not going to find a way to get 12x the memory while still doing the embedded memory packages.

https://www.anandtech.com/show/17058/samsung-announces-lpddr...

> It’s also possible to allow for 64GB memory modules of a single package, which would correspond to 32 dies.

It is possible, and I guess that NVIDIA’s Grace server CPU will use those massive capacity LPDDR5X modules too.

The M1 Ultra has 8 memory packages today, and Apple could also use 32-bit wide ones (instead of 64-bit) if they want more chips.

Do people really need 1.5 TB of unified memory? If you had 128 GB of unified memory and another pool of 1.5 TB or whatever of “slower” memory (more like normal speed on the Intel/AMD side) would that work?

You (or the OS or the chip) could page things in and out if the unified memory. Treat unified memory as a MEGA L3 cache.

Depending on how it’s done it may not be transparent if you want the best performance. But would it work?