RT-AC88U Stuck at 100 Mbps

[PaulWall]

Hey all,

Recently picked up an RT-AC88U and noticed that no matter what I do, I can't get it to negotiate 1Gbps for any of the LAN ports. I upgraded from a (now dead) 68U that was flashed from T-Mobile junk back to vanilla and it worked fine for all four ports.

One of my two wired systems showed 1Gbps for a bit, then after I did some cable and port swapping to get the main system up to 1Gbps everything began negotiating at 100 Mbps. I've tried multiple Cat6 and a few Cat5e cables on different ports to no avail. I've also gone from the vanilla asuswrt firmware to Merlin 384.5 since that's what I had on the 68U and still no love.

One NIC is a Killer e2400 on a laptop, and the other is an Intel NIC.

Any help would be greatly appreciated!

Edit: After a reboot (6th or so) the Intel NIC shows as having a 1Gbps connection, the Killer e2400 still does not.

 

[kfp]

That’s weird, is the 88U used?

 

[PaulWall]

That’s weird, is the 88U used?

Nope, fresh out of the box new.

Curiously, I had just restarted the router after letting it sit for a while, and now it shows the PC with the Intel NIC as 1Gbps, but the Killer e2400 is still only getting 100 Mbps.

 

[kfp]

Nope, fresh out of the box new.

Curiously, I had just restarted the router after letting it sit for a while, and now it shows the PC with the Intel NIC as 1Gbps, but the Killer e2400 is still only getting 100 Mbps.

Ok that sounds more reasonable, Killers are trash. See if they have any driver updates?

 

[PaulWall]

Ok that sounds more reasonable, Killers are trash. See if they have any driver updates?

Just gave that a shot, this is a built-in NIC for the Acer GX-792 laptop (long story as to why I have a laptop versus a desktop that involved contracting and business travel) and ran the only driver from Acer's site. I restarted the router, and the computer, and still shows 100 Mbps down. I also checked if it's on "auto-negotiate" in the settings and it indeed is.

 

[kfp]

Always go straight to the source, though reading through the changelog I don't see them fixing anything related to ethernet speed.
And seems like this is a fairly common problem for this model. :/

 

[kfp]

Maybe install the Control Center software and see if there are anything configurable in there.
I had a Killer AC and I remember I needed to tweak something with it to make it bearable.

 

[PaulWall]

Just went through and removed the older Killer whatever it was called center and installed the new one. Same deal.

I'm now beginning to wonder if a USB-C 3.1 hub with an Ethernet connection is worth it or if finding a way to force said port to 1Gbps is an option.

 

[kfp]

I'm now beginning to wonder if a USB-C 3.1 hub with an Ethernet connection is worth it or if finding a way to force said port to 1Gbps is an option.

Unless you have a use for the hub otherwise just go with a plain USB-C to Ethernet adapter. I’d do this personally instead of trying to fix the Killer.

I’ll Google it some more tomorrow and see if we’ve missed anything.

BTW, did the Killer have problems with the 68U? Can you examine the physical port of the Acer and see if there is damage? How did your 68U die? I wonder if it’s related..

 

[Grisu]

did you try to connect this killer to another 1G ethernet port of PC or other device than 88U to see if it will works there?

 

[Dingus]

https://ibb.co/c8LFE8

Did you try going under the PC's network settings to see if the 1Gb connection speed option was available? If it doesn't show listed like in this image from my PC then it either means the network card doesn't support it or it's a bad cable (had that once..) Could even be driver related or Operating system also had this problem... Make sure to select it to 1GBs if it's there and reboot and do an ipconfig/all and Ping test using CMD make sure the latency is good and speed tests are optimal

 

[PaulWall]

So I wake up this morning and start on the computer to do some work and lo and behold the NIC somehow negotiates a 1Gbps connection. No idea why or how, but both my router and the NIC itself have somehow worked it out, at least for now.

For the record I had restarted the PC and let it sit for a few hours while I went out on the previous day. I have done nothing this morning. The mysteries of auto-negotiation.

@Dingus for the Killer e2400 they have stated that only Auto-Negotiation will work for 1Gbps connections that there is no way to manually set it in the card's settings.
@Grisu I had tried connect it to my modem directly before the 88U and it first didn't negotiate properly, then did after a restart.
@kfp 68U died due to an unrelated event when it was disconnected completely, and the port itself looked/looks fine.


Thanks for the help and your time guys. For the time being I'm going to keep my fingers crossed and see if the router and my computer can work together peacefully and properly.