Legacy isn’t a good explanation because the instruction decoder that turns x86 instructions into microcode is basically a fixed cost and makes up a tiny portion of the silicon. Clearly there is room for innovation in the x86 sphere as well because the AMD Zen architecture was created brand new from scratch and has become very competitive.
The more likely explanation is that there is an exponential difficulty curve in CPU optimization and performance that Apple and their admittedly talented engineers are climbing very quickly.
When an Ax chip hits true desktop performance sooner than later, the limit of physics is going to slow down Apple just like it has Intel and AMD. There isn’t any magic they are going to be able to do that suddenly gives them a 2x IPC gain or huge frequency advantage.
The more likely explanation is that there is an exponential difficulty curve in CPU optimization and performance that Apple and their admittedly talented engineers are climbing very quickly.
When an Ax chip hits true desktop performance sooner than later, the limit of physics is going to slow down Apple just like it has Intel and AMD. There isn’t any magic they are going to be able to do that suddenly gives them a 2x IPC gain or huge frequency advantage.