One of the thoughts on how a mac pro would work was to make the SOC/Memory combo an Add-in card and then use an Infinity Fabric-like interconnect on the motherboard with some nutty controller to allow clean intercommunication to split off instructions.
By doing this, massively multithreaded workloads would not see any real impact...as long as you don't need to send anything card-to-card. Finally, (assuming the M2 Ultra maxes out at 192Gb ram ) this enables adding in 1 to maybe 6 M2 Ultras, topping out just over 1TB ram. This almost starts to work but will fail if your tasks can't be cleanly cut up into 192GB chunks, maybe that's the magic of that controller.
By doing this, massively multithreaded workloads would not see any real impact...as long as you don't need to send anything card-to-card. Finally, (assuming the M2 Ultra maxes out at 192Gb ram ) this enables adding in 1 to maybe 6 M2 Ultras, topping out just over 1TB ram. This almost starts to work but will fail if your tasks can't be cleanly cut up into 192GB chunks, maybe that's the magic of that controller.