Having recently changed over from a hub3 to a hub4 I am now having constant problems with wi-fi download speeds. When I was using a hub3 it was very quick and I never experienced any problems. I can't even facetime now without constant connection problems or look at videos online. Rebooted the hub several times, its ok for a while then reverts to being slow. It is in the same position as the old one. What can I do?