Love your idea of HBM on top of the chip. I've been saying for years that limiting memory to the edges is going to be an inherent physical limiter. I think the only reason it hasn't become more of a thing is that chip size has also been increasing with increasing compute. What about HBM on the back side of the chip ? Essentially I'm thinking like a soldered on piece or another "socket" with pins like a CPU in the bac…
I think the switch to GaN is already happening for power, but Si is considered better for logic dies like the GPU. Also GaN is worse thermally than Si so the problems are actually amplified