RT-AX86U very slow 2.4 GHZ but fast 5 GHZ

[Waylo]

You have to set more realistic expectations:

Understanding Wi-Fi 4/5/6/6E/7 (802.11 n/ac/ax/be)

That's a good resource, but I don't see the part where just moving from an AC router to an AX router gives me 3-4x slower 2.4ghz speeds on an AC capable device?

I'm going to try removing YazFi and start again from there.

 

[drinkingbird]

That's a good resource, but I don't see the part where just moving from an AC router to an AX router gives me 3-4x slower 2.4ghz speeds on an AC capable device?

I'm going to try removing YazFi and start again from there.

There are lots of possibilities. But yes, best to start with a clean slate, factory defaults, and see how it works, then add stuff like yazfi etc once you get 2.4g performance that you're expecting. Don't expect more than about 70M throughput (assuming you have 144M 2x2 link speed, which is what most devices support), and that's best case. A 40mhz channel can double that but not only will you be a terrible neighbor for doing that but the additional interference (you'll now be overlapping with every single 2.4g in range along with bluetooth, your microwave, etc) could actually result in lower throughput than 20mhz. In fact I think some asus routers default to 20/40 so that could actually be causing your problem, change it to 20 only if so.

Newer hardware has implemented newer features. You'll need to play around with some of the 2.4G advanced settings. If you have bluetooth coexistance enabled, try turning that off (or if off, try enabling and try both modes). If it allows you to disable AX on 2.4Ghz do that also and just have it be N (2.4Ghz on an AC router is just N, no such thing as 2.4Ghz AC). Try different beamforming settings (including disabled), different channels, etc. May be as simple as your old router was grabbing one channel and your new one is using a different one with more interference. Make sure airtime fairness is off (which I think it is by default). You can try enabling that but I've never seen it increase speed to a single device, usually it reduces speed for a single device but lets multiple devices get equal amounts of bandwidth (but the sum of them will still be less than with it disabled).

There have been various non-standard technologies to boost throughput on 2.4 and its possible the newer routers don't have that anymore, or have a version of it that is not compatible with your clients. But you should be able to get somewhere between 40 and 75. However I did troubleshoot one scenario for a friend who was in a large apartment complex and no matter what I did, it fluctuated between 1M and 20M wildly. There was just far too much 2.4Ghz around, several people running 40mhz, many using channels other than 1/6/11, etc.

 

[Waylo]

There are lots of possibilities. But yes, best to start with a clean slate, factory defaults, and see how it works, then add stuff like yazfi etc once you get 2.4g performance that you're expecting. Don't expect more than about 70M throughput (assuming you have 144M 2x2 link speed, which is what most devices support), and that's best case. A 40mhz channel can double that but not only will you be a terrible neighbor for doing that but the additional interference (you'll now be overlapping with every single 2.4g in range along with bluetooth, your microwave, etc) could actually result in lower throughput than 20mhz. In fact I think some asus routers default to 20/40 so that could actually be causing your problem, change it to 20 only if so.

Newer hardware has implemented newer features. You'll need to play around with some of the 2.4G advanced settings. If you have bluetooth coexistance enabled, try turning that off (or if off, try enabling and try both modes). If it allows you to disable AX on 2.4Ghz do that also and just have it be N (2.4Ghz on an AC router is just N, no such thing as 2.4Ghz AC). Try different beamforming settings (including disabled), different channels, etc. May be as simple as your old router was grabbing one channel and your new one is using a different one with more interference. Make sure airtime fairness is off (which I think it is by default). You can try enabling that but I've never seen it increase speed to a single device, usually it reduces speed for a single device but lets multiple devices get equal amounts of bandwidth (but the sum of them will still be less than with it disabled).

There have been various non-standard technologies to boost throughput on 2.4 and its possible the newer routers don't have that anymore, or have a version of it that is not compatible with your clients. But you should be able to get somewhere between 40 and 75. However I did troubleshoot one scenario for a friend who was in a large apartment complex and no matter what I did, it fluctuated between 1M and 20M wildly. There was just far too much 2.4Ghz around, several people running 40mhz, many using channels other than 1/6/11, etc.

A fantastic summary, thank you!

After uninstalling YazFi and futzing with some of the suggested settings, I believe I am seeing improved speeds. I re-installed YazFi and so far it seems stable.

I will pull the AC68U out of storage just to see what kind of settings I last used.

EDIT: Turns out I was being a terrible neighbor on the older router and was on 40mhz!

 

[128bit]

the "legacy" setting on the 2.4 really sucks the life out of throughput. as mentioned, it can be slow. that said, when i'm within 15', i have broken 100. rare though.

 

[128bit]

Hi. i just purchased the Asus RT-AX86U yesterday. I have searched the forums and set it up as recommended. When i am at a good distance from the router, my download speed on the 5 GHZ is 210 MB/S. (My spectrum internet is 200 MB/S) When i switch to the 2.4 GHZ, my download speed is 10 MB/S. Does this sound right? Why would the 2.4 be so slow in comparison? Thanks.

fwiw, 200 has been replaced with 300 for the same $ in my geo. they also have a campaign where i was able to get this new speed for 50-$55/mo for a year, as opposed to the 70 -$75 i was paying for 200 and would have been for the updated speed. my suspicion is that they just upgrade customers silently but not sure.

u may wanna call spectrum especially if u want that cheaper price for a year. when i learned about it a few weeks ago, i was calling them to cut back from 400. surprisingly, i can still get low speeds on the 2.4 radio even with the 50% increase but that's another story.

 

[8helge8]

The same. It's just poor implementation of 2.4GHz on Asus Routers.
RT-AX58U Firmware Version: 3.0.0.4.388_23925:
2.4GHZ - 20-80 mbit/s
with 5Ghz band I can even access 600+ mbit/s on my phone