For 3 display to work on AMD card. One screen must be plugged to the display port. If you don't have a monitor that connect via display port, you need an active adaptor.http://support.amd.com/us/eyefinity/Pages/eyefinity-dongles.aspx
That list is not absalute. You don't have to buy the ones suggested on the list. It is just there to help you as a guideline.