I have Sophos UTM with an Internet Speed of 200mbps bridged mode by ISP.
But my wireless AP15 doesn't have the same speed. I only get 10mbps max.
Did you verify that the link and wire you are using to the AP isnt broken?
See if you attach a client to that wire the autoneg gives you 100M or 1G?
Not sure if AP15 can provide more speed though, what do the specs say?
I have several AP100 connected to my UTM, they seem to max out at around 250mbps. I have a 10G uplink to my ISP and Gigabit to the APs.
It's not broken or something. I have another router and it gives the same speed as my AP15.