I have finally got around to doing some speed tests on my network. I'm seeing that the actual WIFI performance is around 50% of the advertised link speed in the status page. Is this normal?
By comparison on the wired Gigabit connections perform close to actual gigabit speed:
Modulation rates and throughput are different things. To get close to the modulation rate you'd need all the time slots, which doesn't happen in operational systems. Beacons, other clients, noise bursts, and the like all impact sustained throughput.
at least 6% of raw bitrate is used for packet headers
wifi is half-duplex thus the returning ack-packets use the same path and bandwidth, thus create "interference" for the actual dataflow, but wont be added in the result by iperf (iirc)