Earlier quoted context omitted.
> I wonder how many out there seriously think we could ever completely rid ourselves of the CPU. How do you class systems like the PS5 that have an APU plugged into GDDR instead of regular RAM? The primary remaining issue is the limited memory capacity. I wonder if we might see a system with GPU class HBM on the package in lieu of VRAM coupled with regular RAM on the board for the CPU portion?
I don’t think the remaining issue is memory capacity. CPUs are designed to handle nonlinear memory access and that is how all modern software targeting a CPU is written. GPUs are designed for linear memory access. These are fundamentally different access patterns the optimal solution is to have 2 distinct processing units
gpus have had cache for a long time. cpus have had simd for a long time.
it's not even true that the cpu memory interface is somehow optimized for latency - it's got bursts, for instance, a large non-sequential and out-of-page latency, and has gotten wider over time.
mostly people are just comparing the wrong things. if you want to compare a mid-hi discrete gpu with a cpu, you can't use a desktop cpu. instead use a ~100-core server chip that also has 12x64b memory interface. similar chip area, power dissipation, cost.
not the same, of course, but recognizably similar.
none of the fundamental techniques or architecture differ. just that cpus normally try to optimize for legacy code, but gpus have never done much ISA-level back-compatibility.