Just got my N66u setup yesterday, and i'm disappointed in the 2.4 band right now. When my laptop is connected to the 2.4 band, i get the full 50+ mbps that my internet offers (comcast). However, when i connect to the 2.4 via my iPhone 5, and run speedtests, i get around 19mbps, then if i run speedtest again, i sometimes get 25mbps, 30mbps, even up to 40mbps. This is all from 2 feet from the router. I've changed the channels around, and also enabled 40GHz. Can't figure out why the speed changes so much. The 5GHZ band works great, and gives me full speed.