It would be interesting to know how important the ARM instruction set is to Apple.
Seriously though, I suspect that the ISA isn't that important for Apple but on the other hand I think they're probably quite happy with the direction of the Arm ISA (probably had a big say in parts of it) and it would take quite a lot to push them away.
I think that the odds on the Nvidia takeover are quite small by now so don't think a move likely at all.
Will RISC V do what ARM did to x86? Start at the low end, be more open, and slowly take over.
The Nvidia purchase is irrelevant to Apple. They have a license that won’t be impacted.
The only thing that would make them move away would be a performance bottleneck in the architecture that necessitates a shift.
Large companies like Apple have an architectural license and implement the entire instruction set on their own.
I worked for a couple of companies with ARM architectural licenses and there was a large ARM compliance suite of tests that had to be run and pass before you could claim that you made an ARM instruction set compatible CPU.
I have heard that Apple does not claim ARM compatibility and doesn't run the compliance suite which allows them a few shortcuts and other optimizations. Apple only cares about running Mac OS and iOS on their hardware so if they were incompatible with Linux/ARM or Windows/ARM they wouldn't really care.
I haven't been able to verify this. Linux/ARM seems to be running okay so far on the new Apple M1 chips.
I don't know if Apple would be affected much if Nvidia buys ARM. Their architecture license to implement from scracth is probably forever but maybe not
Agree with the point 100% but Apple also has a history of long and sustained investments in key parts of the stack where it sees long term value - including compilers and silicon - and long relationships with suppliers. I suspect their relationship with Arm is in that category and so in the absence of something that is demonstrably better, then that will continue.
