It's on-die, but it's not really any faster. The latency and bandwidth are pretty OK by today's standards. I suspect it's on-die because M1/M2 grew out of mobile CPUs. You might be referring to fast SSDs, but that's mainly true only for Pro versions. People who need >32 GB RAM usually know why they need it, you cannot really be running simulations out of your SSD swap. I'm not saying it's a proper use-case for a MacBook, I'm just saying that this guy might have some special requirements that do not align well with Apple laptops price-wise.