I wonder if we can go to even higher density. From entropy constraints, computing performance asymptotically scales with surface area [0,1]. The general bound is Bekenstein bound[2]

[0] https://en.wikipedia.org/wiki/Black_hole_thermodynamics

[1] https://en.wikipedia.org/wiki/Holographic_principle

[2] https://en.wikipedia.org/wiki/Bekenstein_bound

The bound exists, but it's so many orders of magnitude out that for all practical purposes we don't need to worry about it.

Of course, however, heat dissipation presents similar challenges.

It'll be interesting to see how/if quantum effects will be used in future computing tech (well aside from the whole quantum bangaps in semi-conductors). Effects like thermal super-conductors could enable much higher heat in a given area, perhaps built with quantum dots on semiconductors (IIRC, I thought some researchers tried that).

I guess if we hit the edge of feature density, we might start building things out of 3d FPGA type designs of homogeneous modules but because of heat, the capacity of such a design is ultimately going to be limited by its surface area, not its volume, no?

My CPU is a sphere!