I appear to have exactly the same issue issue above too. Latest firmware - ran iperf3 - same result as posted above

@FreddoFrog please have a check of your message box for more details;

 

And if anyone had the same issue, here is something you need to confirm:

1. In this thread, it is only referred to the limited LAN speed (wired or wireless), the internet speed is not affected or mentioned;
2. Did your issue start just after the firmware upgrade?

Then, please leave me a private message with the following details:

1. Can I have a picture of your network topology?
2. How did you run the iperf test, such as on which devices(model info, adapter info), how are they connected to the Deco?
3. The whole iperf speed test results;

Thank you very much.

I had the same issue too . im using unifi 300mbps speed . Previous im using Deco M5 model . it runs well , speed test was 290mbps sometime 310mbps . great . but once i change to Deco X20 model , the speed test cap at below 100mbps only . then i change back to M5 , 290mbps . after tat i change to Deco X20, i get 80mbps . this is confirm X20 issue . and my Firmware is latest one . how come ?

 

I get some solution : when i put near to X20 2meter away, then i can get 330mbps . but once i move to 6meter away , it get only 30mbps. this is worse than deco M5 . so regret i bought X20