Apple’s announcement today that it is moving the Mac to its ARM-based A-series processor chipset is indeed historic. And now that we know its plans, we can examine what the firm is undertaking and compare it to the similar effort by Microsoft part to port Windows 10 to ARM.

At a high level, one might argue that both companies are chasing the same dream, to bring a legacy desktop OS to a more modern and mobile hardware platform. But that’s where the two diverge.