Asus AC88U (RT3100) Poor performance. Ridiculous Pings!

[Nick Darley-Jones]

Good afternoon,

Before I start shouting at Asus for a second time (this is the second router from them) I thought I would see if anyone on here has any advice.

Overview: Pinging the router via wifi gives a response time anywhere between 1000ms and 2000ms. Pinging from LAN approximately 600ms - 900ms. Perform a reboot and the ping goes down to 1ms but then eventually reverts to poor performance after a small amount of time.

I've factory reset the router, tried different firmware, and tried on different computers. It appears to be the router and not the devices connecting to it. Downloading a 40MB file from the internet when I get high latency takes about 30 minutes. After a reset the same file takes a couple of seconds.

Any suggestions before I start demanding another one or a refund?

 

[RMerlin]

Remove devices from your network and add them one by one. That kind of issues can be caused by one single device flooding your network - I can't see any other reason why ping times to the router itself would be that high.

 

[ColinTaylor]

It's a long shot but in addition to what Merlin said, unplug any USB devices from the router just in case that is causing the problem.

 

[Nick Darley-Jones]

Thanks for your help.

I did suspect the 8TB USB Hard drive as being a possible cause but didn't see any evidence. The drive takes a while to be detected so it's possible that's why it doesn't happen immediately following a reboot. However that being said the router should work with it connected.

There are no other devices connected physically, via Wifi I just have my phone and a Raspberry Pi 3 running a local Minecraft server (Raspbian). There is no access to the Raspberry Pi from the outside world.

I'll try another reset and disconnect both to see which causes the problem when reconnected.

 

[Nick Darley-Jones]

Interestingly, I did a ping test and it was reporting about 6 - 8ms. Turned off all other devices abd it was fine. As soon as I unplugged the USB cable from the router the ping went up to 2000ms - 3000ms. Just performed a reboot and will see if it misbehaves without a USB device being connected.

 

[System Error Message]

wifi uses the CPU, check your CPU usage. If it is full it could cause high pings.

 

[RMerlin]

wifi uses the CPU, check your CPU usage. If it is full it could cause high pings.

The RT-AC3100 does offload most of it to the BCM4366 chip tho, CPU usage shouldn't be that high.

 

[System Error Message]

The RT-AC3100 does offload most of it to the BCM4366 chip tho, CPU usage shouldn't be that high.

no but if something else is fully using the CPU it can cause wifi to be slower as wifi is connected to the CPU and not the switch chip. Typically having wifi connected to either the CPU or switch chip has its benefits and drawbacks but when the CPU is pegged by something (like trying to use an 8TB usb drive) it can cause wifi to be slow because of the CPU being fully used.

 

[RMerlin]

no but if something else is fully using the CPU it can cause wifi to be slower as wifi is connected to the CPU and not the switch chip. Typically having wifi connected to either the CPU or switch chip has its benefits and drawbacks but when the CPU is pegged by something (like trying to use an 8TB usb drive) it can cause wifi to be slow because of the CPU being fully used.

The GMAC3 architecture used by the AC88/AC3100/AC5300 allow wifi to bypass the CPU for most of that now.

 

[System Error Message]

The GMAC3 architecture used by the AC88/AC3100/AC5300 allow wifi to bypass the CPU for most of that now.

Depends on whether or not ASUS implemented it that way. In the case of it not going through CPU there could be something spamming on layer 2, but the ping goes through CPU.