I could see them doing something like that. Just in case you didn't have a video card. But the thing is the PCIe slot should over rule the CPU.
When you have a video card in place. That is the way it should work. But again you are dealing with the problem child Z87 boards.
You know the funny part about this is that they should put something in there. To tell you to disable that if you are using a video card.
The only reason I put that up was that is the first thing that shows up in the book. Who would have thought that they would put that about the CPU.
Just a few lines down in the book too. Let see here let's flip a coin to see what one we want to boot from.
Oh what the hell we'll enable both of them. That way we have a 50/50 chance one will work.