RT-AX86U wireless suddenly got slow

[JimTechGuy]

I've had a RT-AX86U for 3 months and it was working great. I have 1 gbps internet to my home, and the router had a consistent wireless signal between 750-800 mbps.
Yesterday, for some unknown reason, the wireless signal dropped to 450-500 mbps. I'm still getting 900-950 mbps through a wired connection to the router. I've tested the wireless signal on multiple devices so I know it's not my computer.

I've spent hours today here and on the phone with Asus trying to get the wireless speed back up to normal. I did a hard factory reset, cleared all the setting (multiple times), and set up totally new networks following the guidelines I've read here (new SSIDs, etc). Eventually Asus said they had to escalate to their high-level tech, but who knows how long that will take. They also offered to send me a new router - that will take several weeks and I'll have to put a temporary hold on my credit card.

I was curious if anyone here has ever experienced an issue like this, or has any suggestions on how to fix it. Thank you!

 

[bbunge]

I've had a RT-AX86U for 3 months and it was working great. I have 1 gbps internet to my home, and the router had a consistent wireless signal between 750-800 mbps.
Yesterday, for some unknown reason, the wireless signal dropped to 450-500 mbps. I'm still getting 900-950 mbps through a wired connection to the router. I've tested the wireless signal on multiple devices so I know it's not my computer.

I've spent hours today here and on the phone with Asus trying to get the wireless speed back up to normal. I did a hard factory reset, cleared all the setting (multiple times), and set up totally new networks following the guidelines I've read here (new SSIDs, etc). Eventually Asus said they had to escalate to their high-level tech, but who knows how long that will take. They also offered to send me a new router - that will take several weeks and I'll have to put a temporary hold on my credit card.

I was curious if anyone here has ever experienced an issue like this, or has any suggestions on how to fix it. Thank you!

What are your WIFI settings?

 

[DarrylJ88]

Jim, my only suggestion although probably not too helpful - is to ensure you've not got any new wireless devices in and around the router that would interfere. Maybe check the wireless channels in your area too to ensure you're on the least congested channel possible

 

[itpp20]

Set your 5g channel fixed to any of these: 36, 40, 44, 48, 149, 153, 157, and 161

 

[duckpond]

i posted a somewhat similar issue, but didnt get much help back as it seems to be an odd issue. I am also on a 1gbit fiber connection

my ax86u if i move in range of it with my s22 ultra, it limits link speed to 1gbps and i get a max of 150Mbps download, if i disconnect from the ax86u wifi and reconnect from the phone, it returns to normal speed and link speed of 2.2Gbps

this only happens on the ax86u, my main router is an ax11000 which does not suffer the issue

i must try factory reset it again to see if it fixes things

 

[JimTechGuy]

I've switched control channels to least used. It's slow on all channels. Qos is disengaged. Attaching screen shot of wireless settings. I even switched to Merlin firmware today but wireless speed did not improve.

 

[itpp20]

What if you disable wifi6? or set 80mhz max.

 

[JimTechGuy]

I tried disabling wifi6 and setting 80mhz max. It ran even slower.

 

[itpp20]

What are the signal levels? -> wireless log, noise and rx/tx & rssi values of a few devices. Is DFS state idle?

 

[JimTechGuy]

Thank you.
Attached is a screenshot of info. noise = -90 dBm, RSSI = -41 dBm, tx = 1200 mbs
I'm running a MacBook Pro 2021 M1 Max on my network, so not sure how to check the DFS state (though I've confirmed same slow wireless speed on ipad).
I have the full diagnostic wireless log; is there specific info you'd like off that? (not sure I want to post the whole log to public forum).

 

[itpp20]

It states 1200mbs, thats not slow for 5g at 80mhz, that excellent! so we can exclude the wifi connection to the AP, must be something at the ISP side (WAN) or on your macbook.

DFS state is on the same log page:

It should be idle, zero time used.

 

[JimTechGuy]

So are you saying that based on that Tx rate that my router is functioning properly?
What could it be on the ISP side? I've had my provider (Frontier) reset the modem from their end, and unplugged it and let it reboot several times, but problem persists. Is it possible that this is an Apple-related issue with an Asus router? What's weird, as mentioned in the first post, is that everything was working fine until a few days ago when this slowdown started.

Re: it being my macbook, I've also tested the wireless internet speed on my iPad and it is exactly the same as on my macbook; both are at 500mbs. So that led me to conclude it's not my macbook (since the iPad has a max thruput of 800mbs). It'd seem like too much of a coincidence for them to separately both be experiencing the same issue and be receiving the same (slow) wireless speed).

I have looked extensively on my macbook but cannot find where the DFS State is listed. It's not on the same log page as that other information. When I run a full wireless diagnostic, a folder is created with 50 or so files. I'm attaching screenshots of those files- is there one that would contain DFS information?

 

[itpp20]

DFS state is on the log page of the router not your macstuff.
If DFS is not idle this can cut speed by half, if not more.
Its on the same router page where you find noise and speed values.

 

[JimTechGuy]

Thank you!!! And sorry for the delay response. The speed actually jumped back to its normal speed for a few days and then dropped back down tonight.
Tonight I located the DFS state on the router. You were right! It was not idle. I made sure it's disabled now with Auto channel and have the DFS box unmarked (is that the best way to do it?)
Unfortunately it doesn't seem to have affected the speed very much -- still slow. Because it went back to normal for a few days and then slow again -- without me anything changing on my end -- I'm starting to suspect there's a hardware issue with the modem and I should just go ahead and swap it out for a new one. It doesn't seem like it should randomly fluctuate like that.

I just looked at the wireless log status: Noise= -90 dBm. The Rx/Tx value was fluctuating quite a bit -- the Tx stayed at 1200, but the Rx went as low as 6 and up to 1080. Is it normal for it to fluctuate like this? RSSI= -56 dBM.

Again, thank you so much for the help!

 

[itpp20]

The theoretical max is 1366 for 5g at 80mhz (I think), so 1200 is not bad given the usual overhead. Rx (and Tx) going down to near zero is normal, if there's nothing to do it should scale down to near zero.

When it goes down to 'slow' and Tx/Rx are near 1366, do a speedtest, if at speedtest-time tx/rx also stay in that range and the test is slow then its something with the ISP modem and not Wifi.