I have a brand new RX 480, connected via HDMI 2.0. When outputting 1080p to a Sony XBR-65X810C, the output matches the screen size. However, when output 4k (directly to the TV, or through a receiver), there is overscan. It appears to be zooming something.
Also, when I connect this through a receiver, the CEC (remote control through HDMI) 'disappears'. Two different receivers have the same issue.
For the above, I've tried multiple cables and configurations, but none of them appear to work correctly.