Speed drops to around 50%

[JediGarry]

I've got an AX58U and for some reason, it keeps dropping to around 50% its expected wifi speed (on both 2.4 and 5G). I updated the firmware to Merlin 384.19 and did a factory reset and all was well for a few days.

I'm with BT on there 500 fibre package and after a reset, I'm recording about 420-450Mbps on LAN and about 380-400Mbps on wifi which I'm more than happy with. However, it only stays like this for a few days and then the max speed I can get is about 240-260Mbps over LAN and wifi. I did another factory reset two days ago and the speeds went back up to normal but today they're back down to maxing out at 260.

I'm not changing anything and no other devices are connecting or causing issues I'm aware of. Has anyone had this before or could point me in the right direction for specific settings I need to be adjusting?

If it helps I've done a scan to check to make sure I'm not clashing with neighbours' wifi and seems ok to me. One thing I did notice on this table is my max PHY seems quite low compared to my neighbour's wifi.

Any help would be much appreciated, thank you and Happy New Year.

 

[ColinTaylor]

The reason you're seeing 866 PHY rate is because your router only has two spatial streams for transmission. See here for an explanation.

But as you're seeing a drop in the wired speed as well this indicates that's it's not a WiFi issue. I am not familiar with how BT's fibre offering works but is it possible that the problem is with their equipment rather than your router? Does rebooting the BT modem/ONT also resolve the issue?

 

[JediGarry]

Thanks, @ColinTaylor for the quick reply. To get BT and their equipment out the way I got onto them a few weeks ago and along with rebooting their modem a number of times and they've also checked the exchange etc and can see no fault there.

I know that next door my neighbour has a router provided by Sky which I was under the impression to be fairly basic so disappointed to see my router not capable of four streams/faster throughput.

What is strange is that after I do a factory reset the router performs very well and can't fault it, it's only after 2/3 days that the speed starts to deteriorate. Any other ideas?

 

[OzarkEdge]

Thanks, @ColinTaylor for the quick reply. To get BT and their equipment out the way I got onto them a few weeks ago and along with rebooting their modem a number of times and they've also checked the exchange etc and can see no fault there.

I know that next door my neighbour has a router provided by Sky which I was under the impression to be fairly basic so disappointed to see my router not capable of four streams/faster throughput.

What is strange is that after I do a factory reset the router performs very well and can't fault it, it's only after 2/3 days that the speed starts to deteriorate. Any other ideas?

The X58U specs are easy to confirm on the product website:
2.4 GHz 2 x 2
5 GHz 2 x 2

2x2 is usually good enough for most clients.

When LAN speed degrades, does rebooting (not resetting) recover speed?

Have you tried wiring your PC directly to the ISP box and measuring speed when it has degraded through your router?

OE

 

[JediGarry]

@OzarkEdge Sounds fair as when the router is working 100% the 2x2 "limit" hasn't been an issue.

A standard reboot of the router does not recover the speeds on LAN or wifi. Only doing a factory reset restores the speeds.

I can't wire directly into the ONT I'm afraid.

 

[ColinTaylor]

A standard reboot of the router does not recover the speeds on LAN or wifi. Only doing a factory reset restores the speeds.

That's very strange. Have you tried simply powering off the router for 15 minutes and then turning it back on again, effectively emulating the amount of time the factory reset would have taken?

I can't wire directly into the ONT I'm afraid.

Is this a physical restriction? Do you not have a laptop you could use temporarily?

 

[OzarkEdge]

That's very strange. Have you tried simply powering off the router for 15 minutes and then turning it back on again, effectively emulating the amount of time the factory reset would have taken?

Good thinking!

OE

 

[JediGarry]

@ColinTaylor I left the router off earlier for about 20 mins and still the same.

 

[JediGarry]

Quick update: I popped the latest stock Asus firmware on just now, ran a factory reset and speed is back up to expected (see first post). Will run with this and see how it goes.

 

[JediGarry]

Another update: I'm not 100% sure but I think I've found the issue or a contributing factor. I use the Asus app on my iPhone and when I set up an access schedule for a couple of my son's devices, the speed degrades over the next 2-4 hours until it settles to around 50% of what the speed should be (the point of my original post). I did this on Friday night and by 10/11pm the speeds had gone back to being slow.

Removing the schedule and even deleting the app doesn't do anything. I did another factory reset on Saturday morning. I have not used the app and so far everything is fine.