I have and rt-ac3100 and Att Uverse fiber. If I directly connect the Att router I get 950mbs down and up. Off the Asus rt-ac3100 I get 50mbs at the most. Qos is off. NAT acceleration is on. I'm on the latest firmware(which I flashed twice during troubleshooting). Wireless speeds are just as slow. also tried other computer/cables and speed tests. The ISP router LAN ports are set to 1g full duplex. I've factory reset the router and i've tried turning on and off every feature I can think of. Any help would be great.