I´m testing my RB wAP ac, and after several tests i detected my tthroughput is very lower.
The RB is connected to a cisco router, and via ethernet cable directly on Cisco
my throughput is 85Mpbs. If i connect through the AP on 5Ghz, my throughput is about 20Mbps.
Not enough information to work with. paste your wireless config for that interface, use command line /wireless export command and delete/replace all sensitive information