It's not. There are fundamental differences in the hardware implementation of handling the instruction codes independent of actual instruction set. This in some

It's not. There are fundamental differences in the hardware implementation of handling the instruction codes independent of actual instruction set. This in some senses is no different than AMD being better at x86 than Intel. My high level understanding is that they integrated a number of components into the chip that typically are external and that they had a trick or two surrounding out of order execution that yielded benefits. Last, they have a more modern manufacturing process and all of this contributes to a significantly better, lower power chip.