RT-AX86U strange slow wifi internet speed

[Jano Drotar]

Hi,
I have RT-AX86U as a main router + 2xRT-AC86U Ethernet connected AiMesh nodes + 1xRT-AX82U 160Mhz wifi connected AiMesh node. 600/120 Mbps internet.
If I am connected to AiMesh nodes, I can reach 450-500 Mbps wifi internet speed on Ethernet connected nodes and cca 150-200 Mbps wifi internet speed on wifi connected AX82U.
But if I am connected directly to AX86U I get 20-25 Mbps wifi internet speed. Wifi connection indicate 1.2Gbps link speed.
After router restart or wifi restart I get usually 500-550 Mbps, but after some time again 20-25 Mbps.
Running Merlin 386.2_2, QoS off, AX on
Tested using Samsung Note 20 and S10.

When I used AC86U as a main router there were no such a issues.
Any idea ? It is strange as connected to AiMesh node that use same AX wifi connection to AX86U as tested mobile phones I can get almost 200 Mbps.
Thanks a lot.

 

[Pavl]

Did you try using the AX82U as your main router? I just tested the AX86U and the AX82U, and I found the AX82U performing 50 Mbps better at times. I would be curious if it's the same for you.

 

[Jano Drotar]

Well, I would not care about 50 Mbps difference, but AX82U does not support Merlin, it's less powerfull and does not have 2.5Gbps port used for NAS.
btw I used Laptop with AC7260 adapter for another test and seems it's working fine in same time when I do have issue with Samsung phone. So I tried to disable NitroQAM and keep testing (after disabling and wifi restart it runs on 500 Mbps, but that happens before as well that some time after router wifi restart it works fine).
btw2 if I used only 2.4Ghz I got ~10Mbps internet speed on Samsung, so seems 2.4GHz band is also affected with this issue.

 

[Pavl]

Well, I would not care about 50 Mbps difference, but AX82U does not support Merlin, it's less powerfull and does not have 2.5Gbps port used for NAS.
btw I used Laptop with AC7260 adapter for another test and seems it's working fine in same time when I do have issue with Samsung phone. So I tried to disable NitroQAM and keep testing (after disabling and wifi restart it runs on 500 Mbps, but that happens before as well that some time after router wifi restart it works fine).
btw2 if I used only 2.4Ghz I got ~10Mbps internet speed on Samsung, so seems 2.4GHz band is also affected with this issue.

Thanks for the reply. I believe I fixed the issue I was experiencing. I didn't realize Merlin didn't support AX82U. I guess I assumed since it would since it supports AX58U.

 

[Jano Drotar]

Disabling NitroQAM did not help.
Testing disabled 802.1ax.

 

[Jano Drotar]

So, seems I found the issue ;-)
It works fine with disabled AX. That would explain why laptop with AC NIC had full speed same time when Samsung AX phones were running on 25 Mbps.

 

[Jano Drotar]

Confirmed Samsung AX implementation issue - https://eu.community.samsung.com/t5...a-slow-wifi-on-asus-router-ax88u/td-p/1647868

 

[Jano Drotar]

Unfortunately even disabling AX did not help. After some time I was getting 2-5 Mbps internet speed. I'm lost ....