@Sunshine So it is. Well that will teach me for assuming that a device boasting, "2.4 GHz (300 Mbps) and 5 GHz (867 Mbps) dual-band WiFi" would obviously have a Gigabit ethernet port, so that someone...

I have the 315 set up as an access point connected to my router by Cat5E cable. If I plug that cable directly into a laptop I get the full speed of my ISP 1000Mb/1000Mb. But as soon as I plug it back...