Eyefinity display types

Hey thanks for answering my last question regarding my eyefinity 5 setup with msi lightning 7970 with 5 u2412.

Unfortunately i selected the best answer and can't post on that one anymore. Though your answers were reassuring i came across this. I remembered this is what sparked my near heart attack this morning and i need some education as to what they mean by this.

http://support.amd.com/us/kbarticles/Pages/Screentearin...

From your answers you can mix dvi and display ports, but amd says otherwise. WHY? It seems their article is saying the tearing is happening purely from the mix of display ports rather than a combination of a weak card, bad drivers and mix display ports.