It used to be that the x86 instruction set was representative of the processor architecture that it programmed. That is no longer the case. Now, it is valid to

It used to be that the x86 instruction set was representative of the processor architecture that it programmed. That is no longer the case. Now, it is valid to view the x86 instruction set as an abstraction of the processor architecture. That is, you can mostly pretend that the processor you're programming for is accurately represented by the architecture implied by the x86 instruction set, but it is not. And when it comes to instruction timings, this abstraction leaks. If the term "abstraction" bothers you, then ignore it. The point of the post is to give people perspective.