Does anyone know if 11ac wireless is only effective if all devices on the network use it? I have a new ac enabled laptop connecting to my BT HH5 at 430Mbs but when I switch on my much older laptop the speeds at both machines are 72Mbs(old one) and 130Mbs (new one). I suspect that the new laptop is using the 5GHz band but not the ac option and the old laptop 2.4, as it always does. I do have an ac dongle for the older machine but lent it to a friend to try out - I didn't think that my newer connection would be affected though. The speeds quoted are router to wireless card of course, in the same room as the Hub.
Dell Inspiron 15, Win 8.1, IE11
BT Infinity 2 via HH5