I'm struggling with wireless-n speeds. My house is over 3 floors and the internet comes in on the ground floor. Luckily the stairwells are open so signal travels well up but sides ways the walls are block and the signal gets weak. Wifi traffic comes in from the outside too, airwaves are busy. My airport express (plug in type) running 5ghz at 300Mbps drops to around 5-10Mbps from top to bottom floor. Actually within the same room it will only achieve 300Mbps in direct line of sight. Through a wall it may drop to 230Mbps. Through two walls it is already down to 115Mbps. Because of the wifi congestion on 2.4Ghz i need very strong 5ghz performance throughout all 3 floors. I would like to achieve at least 130-145Mbps on the top floor when the airport extreme is on the ground floor. This will allow the max speed of 80Mbps from fibre broadband. Keep in mind that the airport express is allowing around 5-10Mbps in 5ghz mode when the airport express is on the top floor and i test on the ground floor. Will the new Airport Extreme AC do much better? What do you think?