RT-AX86U erratic speed on ISP connection

thejollyboys

New Around Here
Hi,

I have just replaced my stock BT Hub 2 with this router. I have full fibre 900. With this modem I never get over an average of 600mb on the built in speed test. i get about 450 on and wifi connected device on 5ghz.

Internet speed test on the modem gui goes from 350mb to 750mb, all over the place. Never have is seem, apart from a single split second anything close to 900mb.

I have tried everything i have read so far.

  • Flashed Merlin latest firmware, reset factory defaults still the same. I did get 900mb for a split second, but then back down to 600mb ish.
  • Set the MTU size to 1472, still the same
  • Reflashed latest stock FW, reset factory settings, still the same.
  • Turned off all the enhanced settings AI stuff an QOS are off.
Any help much appreciated.

Thanks.
 
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bbunge

Part of the Furniture
Hi,

I have just replaced my stock BT Hub 2 with this router. I have full fibre 900. With this modem I never get over an average of 600mb on the built in speed test. i get about 450 on and wifi connected device on 5ghz.

Internet speed test on the modem gui goes from 350mb to 750mb, all over the place. Never have is seem, apart from a single split second anything close to 900mb.

I have tried everything i have read so far.

  • Flashed Merlin latest firmware, reset factory defaults still the same. I did get 900mb for a split second, but then back down to 600mb ish.
  • Set the MTU size to 1472, still the same
  • Reflashed latest stock FW, reset factory settings, still the same.
  • Turned off all the enhanced settings AI stuff an QOS are off.
Any help much appreciated.

Thanks.
Check the Ethernet cable between the ONT and the router. Needs to be a CAT5e or better with no kinks or visible damage. Should be a factory made cable unless you are skilled at making Ethernet cables.
Factory reset and initialize all settings should be done at the GUI: Administration/Restore/Save/Upload Setting/Factory Default. Using the Asus Hard Factory Reset method may not fully work for the AX86U (https://www.asus.com/support/FAQ/1039078)

Try a speed test from an Ethernet connected PC to the router and pick a time of day that may not be busy on the BT network.
 

thejollyboys

New Around Here
Just to be absolutely sure this is the case, go to Administration > Privacy. If there's an option to "Withdraw" from the licence agreement do so.
Thanks, I have withdrawn as suggested, it does seem more consistent now. I'm getting more like 800 on average now, where it was a lot lower before. Thank you, I'll monitor today and report back.
 

thejollyboys

New Around Here
ok so today its been a bit up and down but certainly better than it was before but never achieving 900mb.

The other issue now is my wifi now, i seem to be getting about 200mb on an iPhone 12, and about 500mb on a Mac. When i go to fast.com it burst for a split second to 800-900 then fall back down to single figures, finally settling on 200-400mb.

Any help with this, again much appreciated.
 

ColinTaylor

Part of the Furniture
When i go to fast.com it burst for a split second to 800-900 then fall back down to single figures, finally settling on 200-400mb.
I've tried using fast.com occasionally over many years and I've never seen it return a result that was even remotely correct. Maybe for people outside the UK (or with a different ISP) it's more accurate.
 

L&LD

Part of the Furniture
Yes, fast.com results vary depending on the ISP and area of the country you're in. Same for speedtest.net too.

The solution is to not use a single speed test. Rather, get to know all the nuances of your ISP by using multiple speed tests, every time you test for speeds.

Whatever each report, make a note of it and use it to compare it to future results to know if you're in the ballpark with at least one of them (and the others not simply having issues of their own, that day/time).

The internet is one huge variable, this is the best we can do to reduce that variability for this particular 'test'.
 

thejollyboys

New Around Here
Update. It’s still a little up and down and certainly below my guaranteed speed, 700mb with BT most of the day. I’m not sure they would entertain me reporting a speed issue with a non stock router?

What is the best way for me to record the speed at the wan port of the router ever hour? Is there an app or software that can record that kind of stuff. There may well be something in the Merlin firmware to help?

I can then build a picture for BT to investigate.

thanks.
 
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