AC68U 400Mb/s wifi download speed limit?

[JackFrost]

Greetings,

I have a brand new AC68U in hardware revision V3 with latest Merlin software. I have a AC 1550i wifi card in my laptop and 500/30 Mb/s cable.
My wifi connection on laptop and Oneplus phone both report 866,7Mb/s on 5Ghz link yet I cannot go beyond 410-420Mb/s. I tried testing speed with different servers.
My signal strength is around -35/45 dBm. Everything is working fine except max wifi download speed of around 420Mb/s max.
Tested on ethernet and I have 492Mb/s

Tried testing with Adaptive, standard QoS, QoS off but no luck.
Is there a particular limit to the wifi speed in Asus? It was possible to hit almost 500Mb/s on my ISP's stock modem/router Compal CH7465LG before I bought an Asus.

How to solve this or is it by design for some reason?

 

[Ronald Schwerer]

What is your ISP speed supposed to be? Most of use can't get that over wifi regardless of signal strength.
Try turning off QoS (Adaptive QoS tab) Turn off Apps Analysis and on QoS tab turn off Enable QoS. Also turn off AiProtection. After changing the settings, reboot. See if speed improves. If it does, you can play with these to find a happy compromise.
My old (v1)68U overclocked to 1200MHz was able to dn/up around 940 Mbps (wired) from my ISP's server. Other servers shown in Speedtest got less but IDK if their gateway was up to handling 1Gb testing.

 

[JackFrost]

What is your ISP speed supposed to be? Most of use can't get that over wifi regardless of signal strength.
Try turning off QoS (Adaptive QoS tab) Turn off Apps Analysis and on QoS tab turn off Enable QoS. Also turn off AiProtection. After changing the settings, reboot. See if speed improves. If it does, you can play with these to find a happy compromise.
My old (v1)68U overclocked to 1200MHz was able to dn/up around 940 Mbps (wired) from my ISP's server. Other servers shown in Speedtest got less but IDK if their gateway was up to handling 1Gb testing.

Cable 500dl and 30up Mb/s like I stated. I do get those speed over cable but not over Wifi for some reason - or the wifi speed is directly affected by range and the reported link speed is not what I should keep in mind? Still, it is strange that it is capped at 410/420 for both laptop and smartphone.
Tested with QoS on or off, same results and ping. All the Ai stuff, media servers, usb disk stuff, analysis, monitoring etc. and other options are disabled. I always reboot between changing settings just to be sure everything is reloaded correctly.

 

[Ronald Schwerer]

Try turning off 5GHz Beamforming (both types) and Airtime Fairness.

 

[JackFrost]

Airtime was disabled by default, no meaningful change with both beamformings disabled.

I tested it with phone, currently max 385Mb/s on various local and abroad servers. Tested in same room as router, 1-2,5 meters distance. Only one client connected to 5Ghz wifi. I have a feeling there is some sort of invisible ceiling and for some reason it is impossible to hit 500Mb/s on wifi with 866Mb/s reported link to pc/phone.

 

[JackFrost]

Ok, I managed somehow to fix this but fiddling with some options. Now I have 495MB/s (tested couple of times via speedtest.net) through wall and 3 other clients connected. Before I was struggling between 300-400Mb/s nad it wasnt stable, once most of the test were around 320-340 or 370-390Mb/s.
I enabled TX Bursting and lowered Beacon interval from 100 to 50.
Here are my settings, maybe it will help advanced users to tell what was wrong and other user to help solve their transfer speed issues:

WPD/WDS/Radius options disabled or not set, rest as pictured. Latest result is over 505Mb/s with domestic server, abroad 495Mb/s so I am happy if the router settings will be stable - https://www.speedtest.net/result/10463626799