My motherboard (ASUS ROG Maximus XI Hero Wi-Fi) is only letting ethernet go to 100mbs and not a gig for some reason i dont know how to fix it ive changing the speed under the control panel but when i do that it just says there is no cable connected. I would say its the cable but i know the cable is either cat6 or 7 and its worked perfect with gig connect on my last motherboard. Also ive uninstalled and reinstalled the drivers from windows and ASUS.