how to optimise the wifi for ubuntu 16.04, Intel Dual Band Wireless-AC 72

Can anyone give me some advice on how to optimise the wifi for my system (ubuntu 16.04, Intel Dual Band Wireless-AC 7260)?
I have an ac adapter / router and yet the wifi coection is very slow (slower than non-ubuntu systems coectiving via wifi to the same network).
Results of wireless-info attached.
As a workaround, I am currently using etheet and both the etheet and wifi were coected whilst wireless-info was run, but normally I'll only use the one or the other.

Thanks very much for any help.