"What would keep Apple from shipping machines with both ARM and Intel CPUs in them? The ARM CPU would run the OS and decide when to ship jobs over to the Intel CPU. I can’t imagine that the home-grown ARM CPU would add much to the total price of the computer."
It is a lot of work and now you have to buy two CPUs. No cost savings, possibly more power usage in worst case, and maybe even thicker computers.
It would restrict it so you can never remove the Intel CPU. It is best to just emulate the Intel CPU for a while until everyone ports their code across.
Well, in theory both AMD and ARM use MOESI so it's not as crazy as it would be with Intel's MESIF. But that's a really scary rabbit hole to be going down and I'd be terrified of memory permissions attacks striking at the boundary there. So probably not worth the risk unless each processor gets its own pool of RAM.
Ah. I saw references to "dual architecture" online but looks like that means Apple will be releasing new Intel machines even as they are encouraging everyone to port their apps to ARM. The "dual" part just means two different lines of machines that will be sold contemporaneously for a little while, not two architectures inside one machine.
This level of asymmetric processing is very difficult to achieve, at nearly every possible level, from part sourcing, through hardware design, firmware, software to user experience.
"What would keep Apple from shipping machines with both ARM and Intel CPUs in them? The ARM CPU would run the OS and decide when to ship jobs over to the Intel CPU. I can’t imagine that the home-grown ARM CPU would add much to the total price of the computer."
https://news.ycombinator.com/item?id=23530084