Basically the density of early CPUs (1970s), but 1000x faster than those, or current CPUs? Like a 1GHz 6502, or a 1THz 6502? The former is not really better, but the latter might interesting.

There ain't no free lunch, but real progress rarely depend on it. It's usually lunch we weren't eating before, or a different way to eat the same lunch but with much more satisfaction.