RT-AX92U 5GHZ-2 slow (SOLVED!)

[Albert Ma]

I've got a RT-AX92U in single wireless router mode.
smart connect off. Channels manually set.

The 5GHZ-2 band is incredibly slow. I get download rates of 1-10Mb/s instead of 300Mb/s I get on the 5GHz-1 band. I'm just testing a single device right by the router. Great signal strength. Ping times are normal.

I've tried two of the routers, both exhibit the same behavior.

Does anybody have the 5GHz-2 working well, and what did you do?

 

[Jim Gifford]

Enable OFDMA, made a big difference here.

 

[Albert Ma]

thanks, we have no AX devices, so I have AX disabled. Plus I'm just testing 1 device at a time on the 5GHz-2 band. Could that really bring me from 1Mb/s to 300Mb/s?

 

[catch36]

thanks, we have no AX devices, so I have AX disabled. Plus I'm just testing 1 device at a time on the 5GHz-2 band. Could that really bring me from 1Mb/s to 300Mb/s?

Not sure if this will help. I replaced a AC88U with a AX88U and was experiencing similar download speed slow downs on a with a desktop with an Broadcom A/C adapter. Disabling " but enabling "WMM APSD" on the 5GHz channel fixed my download speed problems. WMM APSD was putting the adapter into power save mode. Also I have better download speeds on the lower channels in my area.

 

[armelwani]

I had the exact same problem. Found the issue was I had QoS turned off. Turned it on and all issues went away. Because I don't actually need QoS, I switched it to the option of Bandwidth Limiter and didn't put any devices into it. Everything works fine now. Attached is a screenshot of my QoS settings. Hope that helps!

 

[Albert Ma]

I had the exact same problem. Found the issue was I had QoS was turned off. Turned it on and all issues went away. Because I don't actually need QoS, I switched it to the option of Bandwidth Limiter and didn't put any devices into it. Everything works fine now. Attached is a screenshot of my QoS settings. Hope that helps!

Wow, that works. That's crazy. This needs to be a FAQ

 

[K-2SO]

Wow, that works. That's crazy. This needs to be a FAQ

This is not a solution. On many routers Bandwidth Limiter disables HW acceleration. Unrelated to WiFi performance. Not what you describe as a problem. With no HW acceleration this is not a Gigabit router anymore.

 

[Albert Ma]

This is not a solution. On many routers Bandwidth Limiter disables HW acceleration. Unrelated to WiFi performance. Not what you describe as a problem. With no HW acceleration this is not a Gigabit router anymore.

well, with bandwidth limiter I'm still able to saturate my 300Mb/s link on the 5GHz-1 channel. The 5GHz-2 channel is only getting 200Mb/s (on a two antenna device), so still some tweaking to do. A vast improvement over 300Mb/s and 1Mb/s I was getting before. CPU load is still minimal.

certainly I agree this setting shouldn't help, but it does. Hopefully ASUS will have a firmware fix at some point.

 

[K-2SO]

certainly I agree this setting shouldn't help, but it does. Hopefully ASUS will have a firmware fix at some point.

I see @AndreiV uses RT-AX92U twin pack. He may be able to share with you some tricks.

 

[armelwani]

well, with bandwidth limiter I'm still able to saturate my 300Mb/s link on the 5GHz-1 channel. The 5GHz-2 channel is only getting 200Mb/s (on a two antenna device), so still some tweaking to do. A vast improvement over 300Mb/s and 1Mb/s I was getting before. CPU load is still minimal.

certainly I agree this setting shouldn't help, but it does. Hopefully ASUS will have a firmware fix at some point.

Yup, couldn't agree more. I was dumbfounded when I came across changing that setting to fix the issue. I have a 150Mb/s Internet connection so for me I'm getting the max on all three bands once I turned on QoS and set it like I showed in my screenshot.

Until ASUS releases a firmware fix, this is the only setting I've found that gets the 5GHz-2 usable at all.

 

[AndreiV]

I see @AndreiV uses RT-AX92U twin pack. He may be able to share with you some tricks.

Nope , the only change I made was to turn off AX as I don't use it, that fixed the 5G2 WiFi speed being halved.

Cannot see how QOS can have any bearing on WiFi speed , especially on only one band.

I checked real download speeds against a site with test files of specific sizes and timed them against my actual ISP connection speed , WiFi and ethernet devices give the same, correct throughput rate for my connection.

 

[Albert Ma]

Nope , the only change I made was to turn off AX as I don't use it, that fixed the 5G2 WiFi speed being halved.

Cannot see how QOS can have any bearing on WiFi speed , especially on only one band.

I checked real download speeds against a site with test files of specific sizes and timed them against my actual ISP connection speed , WiFi and ethernet devices give the same, correct throughput rate for my connection.

What is your configuration? Mine is single router.

 

[AndreiV]

What is your configuration? Mine is single router.

Router and hardwired Access Point.

 

[armelwani]

I am a single router, too. I hear what everyone is saying about how QoS should have no bearing on this issue, but it really does, and is easily reproduceable. If I turn QoS off, my 5GHz-2 band drops to about 1Mbps for Internet traffic. Accessing my local LAN stays at full speed. All other bands work fine as well. I turn QoS on, in any mode, and like magic I get full speed access to the Internet on 5GHz-2.

 

[K-2SO]

I turn QoS on, in any mode, and like magic I get full speed access to the Internet on 5GHz-2.

I'm guessing, something is buggy around hw acceleration on this router. Use the band-aid solution for now until Asus fixes it.

 

[deluxeg]

I have the same exact issue with a ZenWiFi AX but turning on QoS did not help. 5Ghz-2 is about 6 Mbps and 5Ghz-1 I can get over 500Mbps.