The CPU's have a GPU built in(not the motherboard). No the cpu does not waste any processing power supporting the video ports(that's what the built in GPU is for).
Yes setting the video to default to the pci-e will disable the built in video.
You'll be happy with that combination.
Thanks very much for your help. The last thing I wanted is being gimped by 4 extra ports that I'm never going to even use. Cheers!