In our experience, deactivating the "QoS" (sometimes part of a "WiFi Multimedia" tab) wireless setting in the router panel (which tends to favor certain kinds of network traffic over others, such as video and gaming) made a dramatic difference in the network efficiency, and in the perceived speed of A.C. in particular. Other kinds of network traffic, such as web browsing, did not typically seem much affected either way.

Anyone looking for a possibility to speed things up a bit should check this setting and make sure that QoS is off.