[cmrdporcupine]

I don't know enough about CPU design to say really but Pentium IV is a long time ago now. And since then, I suspect that a lot of assumptions about 64B line sizes have been baked in.

Apple could go to 128 because they were rolling out a whole new ISA, so were breaking compat anyways.

That said, they have amazing performance on the M1, and I wonder how much of that has to do with the wider L1 size.