This is all very vague theorizing of course, but I believe that once we reach a level of artificial intelligence that resembles biological intelligence, scaling

This is all very vague theorizing of course, but I believe that once we reach a level of artificial intelligence that resembles biological intelligence, scaling it will be quite feasible on a silicon platform. You've also removed the element of maintaining a body (exercise, eating, hygiene) as well as expanded potential interfaces (direct connection to the internet) so that even a 1:1 silicon brain would presumably be more efficient. The next thing you can do is optimize the time step element, so that for every 1 second of thinking in a silicon brain, it has performed the equivalent of 10 seconds of thinking in a human brain. At that point, you've surpassed human intelligence. It's also safe to assume that if we do reach this point, we've learned a lot more about how biological intelligence works, and may be able to use to our advantage the beneficial intelligence properties of savants. The really big downside with all these approaches is that the intelligence will be built from a blueprint that includes emotions, and we may do something that is very morally wrong towards the intelligence that we created.