I replaced my XR500 with a new XR1000. Same location, same cables. Speedtest in the Nighthawk app shows it is running 218.71M down, and 11.36 up. However, none of my devices are receiving better than 89M over wifi, and that was literally right next to the router.
I have the latest firmware (V1.0.0.58) installed and did a reset...no joy. My old XR500 had no trouble getting 180-200M all around my house. I've tested from my PC and only get up to ~50M, but frequently in the 20-30M range. My iPhone and iPad do a bit better, but only if I move close to the router.
