It does sound then that the laptops are selecting the 2.4 network to connect to. To force them onto the 5GHz one, log into the settings and rename the SSID's like this...
Assuming you have the Hub3 on a new package(?) log into the settings and in Advanced>wireless>smart wifi - tick the disable “channel optimisation” box and save settings. Then, go to advanced>wireless>security, rename the 2.4 & 5 GHz network ssid's. Just change 'em to whatever you like and something that will differentiate them (e.g - xxxxx2 & xxxxx5) -- use the same password if you like, Then, apply settings and restart the Hub. Your 2 wifi networks will now be clearly separated - and you can then select the network you want to connect to individually from the "available networks" list on each device. If it doesnt work or you dont like it then go back with a pinhole reset of the Hub
-------------------- John --------------------
My services: HD TV on VIP (+ Sky Sports & Movies & BT sport), x3 V6 boxes (1 wired 2 WiFi,) SH2 in modem mode with Airport Extreme Router. On VIVID200, Talk Anytime Phone, x2 Mobile SIM only iPhones.
Tested my wife's laptop last night - it gave a 210Mbps when using ethernet, and 60mpbs on wifi. Clearly it has settled down and I suspect that is the maximum she will get.
My laptop is a Dell and it turns out it has a Dell-installed programme called SmartByte, which was throttling the connection. Turn it off and the ethernet speed goes to maximum. Wifi to 148Mbps, which again I suspect will be the maximum speed for a wifi connection.