Recently bought a new Arris sb8200. New cat6 cables. Can achieve 950 down directly connected to my PC. When I attach it to my router, it default negotiates to 100mbps full duplex. If I set it to 1000mbps full duplex it immediately loses connection to the modem. Cables are all fine, work individually. Can't find any information online of people encountering a similar issue. Making me crazy. Went and exchanged for a new modem, still no dice. Is my router defunct? I updated the firmware, still no good