Help needed with ASUS rt ax55 (Ethernet speed limiting problems)

[Laantje]

Hi y'all,

I've bought an Asus RT AX55 for wireless VR gaming. When it works, it works great! We have fiber at our building and whenever the router is fine I get around 900 megabits on speedtest.

Unfortunately, I've been dealing with a problem concerning speed which also ruins both my fast internet and my VR experience. For some reason ̶a̶l̶l̶ (EDIT: New results showed that it only applies to a certain device. The other device was always 100mbps limited) my LAN ethernet ports (WAN is fine) keep dropping to 100mbps after a while. If I reset the router, it turns back to 1gbps but around ~30 minutes later its back at 100mbps. I can notice this in VR because I suddenly get a huge delay in tracking movement.

I have absolutely no idea what causes this, I've tried a handful of things which didn't work. Here is the list:
- Updating firmware
- Swapping ethernet cables (They're all good quality as far as I know, one of them is a new bought cat6)
- Changing wire path to make sure my HDMI cable that takes the same path wasn't disturbing the ethernet cable
- Using the router without being connected to the internet, but even then after a while they cap back to 100mbps
- Changing LAN ports

I'm kind of lost, don't know what else to try. Maybe someone here can help me out with this problem

Thanks in advance!

 

[degrub]

grab an unmanaged 5 port Gbit switch and plug one port into a lan port on the router. Directly plug in your users to the switch. What happens ?
If the switch ports to the users on the new switch still change to 100 mbit, then the issue is likely the users (check the lights on the port or in the user OS status).

If the lan port on the router still changes to 100 Mbit, then it sounds like you have a defective unit.

 

[Laantje]

grab an unmanaged 5 port Gbit switch and plug one port into a lan port on the router. Directly plug in your users to the switch. What happens ?
If the switch ports to the users on the new switch still change to 100 mbit, then the issue is likely the users (check the lights on the port or in the user OS status).

If the lan port on the router still changes to 100 Mbit, then it sounds like you have a defective unit.

I did something similar and got new results. Instead of using an unmanaged switch (I only have a 100mbps one here at this moment), I just put in the cable straight into my apartement's wall socket (we have a big shared network in this building divided with VLAN) and it worked, but this way I won't be able to pull of my wireless Virtual Reality experience so I was not satisfied yet. Thus, I kept on experimenting. The results are below:

These are the steps I just did after posting this thread:
1. Plug in cable directly from PC into wall socket (straight to building's internet) and got stable 1gbps
2. Plug cable back into router and its back to 100mpbs after 10 minutes :/
3. Tried forcing the duplex to 1000FD with ssh ethctl, no luck
4. Just remembered I have a reserve PCIE ethernet port card somewhere
5. Found it, installed it
6. Plugged the same cable into that port instead of my motherboard's ethernet port
7. Now been having stable 1gbps for atleast 15 minutes, hopefully this fixed it but time will tell

If it keeps stable then something might be wrong with my ethernet port in my motherboard. But its weird though since a straight connection between my motherboard and the wall socket works absolutely fine, hmmmm.....

Ill post an update if it goes back to 100mbps but so far so good! Fingers crossed....

 

[degrub]

"2. Plug cable back into router and its back to 100mpbs after 10 minutes :/ "

Which port went to 100 Mb/s - the wan port on the router or the lan port on the router ?

 

[Laantje]

"2. Plug cable back into router and its back to 100mpbs after 10 minutes :/ "

Which port went to 100 Mb/s - the wan port on the router or the lan port on the router ?

LAN port on the router connected to my PC.

Still rocking on 1gbps after almost 2 hours on the PCIE card btw so I guess its solved!