Question Realtek ethernet is stuck at 100mbps ?

[gijoe50000]

So I know this issue pops up for a lot for people, and I have tried pretty all of the solutions that I could find, things like changing Speed & Duplex to 1gbps, disabling power savings, etc, but nothing seems to work.
My motherboard is an X570 Tuf, with Realtek Gaming Gbe Family Controller.

I have eliminated my router and my cable from the equation because I can get 1000mbps, no problem, when I plug the same cable (still connected to the router) into another computer, so this pretty much leaves the PC as the culprit.

I also notice that in Windows Settings > Advanced Network Settings > Ethernet: when I change something (like Speed & Duplex) the Link Speed will change to 1000mbps for a few seconds while the adapter is reconfiguring, but once it reconnects it will drop back down to 100mbps again.

I've tried the LAN driver from the ASUS website (10.50.511.2021), and I tried a newer driver from Realtek (1168.16.1123.2023), and even an old Windows 10 driver, but neither will give me the 1gbps speed that it's supposed to have.
I've also checked the port and it all looks clean, and the pins don't look bent or anything.

Anyone have any other ideas or suggestions?

Or could the controller just be flat-out broken?

 

[NanoSuit3]

What kind of CAT cable is it first off?

 

[gijoe50000]

What kind of CAT cable is it first off?

It's CAT 6.

 

[bill001g]

The speed stuff is negotiated at a very low hardware level by detecting voltages it is not software or drivers you can change.

If you really think it is the port you can't fix it. You would have to use something like a pcie ethernet card.

Still 99% of the time it is the cable. It would be nice if a ethernet cable just completely failed when it was bad. Some machine tolerate cables that are out of spec better than some others.

Make sure you use a quality cable. It must be pure copper with wire size 22-24. There are massive amounts of that flat cable being sold that has wires much too thin to be a actual certified ethernet cable. These fake cable since they do not meet the standards work on some machines and not others. Even a quality ethernet cable can be damaged or go bad so I would buy a new cable first.....ethernet ports are not real expensive but plugging in a new cable is easier than opening your machine up and putting in a card.

 

[gijoe50000]

The speed stuff is negotiated at a very low hardware level by detecting voltages it is not software or drivers you can change.

If you really think it is the port you can't fix it. You would have to use something like a pcie ethernet card.

Still 99% of the time it is the cable. It would be nice if a ethernet cable just completely failed when it was bad. Some machine tolerate cables that are out of spec better than some others.

Make sure you use a quality cable. It must be pure copper with wire size 22-24. There are massive amounts of that flat cable being sold that has wires much too thin to be a actual certified ethernet cable. These fake cable since they do not meet the standards work on some machines and not others. Even a quality ethernet cable can be damaged or go bad so I would buy a new cable first.....ethernet ports are not real expensive but plugging in a new cable is easier than opening your machine up and putting in a card.

Thanks for the reply.
But no, I really doubt it's the cable because I tried a bunch of different CAT5e and CAT6 cables, even the ones that came with the router that were never even taken out of the box until now, and they always only read 100mbps.
My main CAT6 cable is a fairly hefty one though, about the thickness of a coaxial cable and 10m long. But it immediately went to 1000mbps when I put my other PC "in place" and plugged it in.

I was even wondering if it could be something to do with PCIE lanes, but I changed around some settings in the BIOS, and even disabled my second NVME, but still it doesn't move from 100mbps.

If it's like you say, at very low level, then I'm thinking it must be something broken around the port at a hardware level..
I might give the port a good clean and visually inspect the motherboard over the next few days and see if there's anything obvious wrong there.

 

[bill001g]

Modern electronics is almost impossible to repair. Everything is so tiny and it is all surface mount so without special equipment you can not think to even replace a defective chip even if you could buy a replacement.

Maybe you bent a wire inside the ethernet port. Those too are fairly fragile and once damaged are hard to fix.

A pcie ethernet card is under $30 you can even get 2.5/5g ones for about the same.

 

[gijoe50000]

Modern electronics is almost impossible to repair. Everything is so tiny and it is all surface mount so without special equipment you can not think to even replace a defective chip even if you could buy a replacement.

Maybe you bent a wire inside the ethernet port. Those too are fairly fragile and once damaged are hard to fix.

A pcie ethernet card is under $30 you can even get 2.5/5g ones for about the same.

Yea, those are some fair points, but I suppose it could also be an excuse for an upgrade, since the board is over 4 years old.. it might be time to jump on the DDR5 bandwagon..

 

[gijoe50000]

So I just randomly saw a zip file in my downloads called "Diagnostic_v2.0.7.3_0801_1.zip" and it turned out to be an ethernet diagnostic tool, no idea where it came from but it may have downloaded with one of the drivers I downloaded last week.

I ran it and it tells me I have a short in the 7-8 pair.

So I ran the test with the cable unplugged and the short is still there:

I think this confirms that there's a short somewhere in the pins, or deeper inside the controller/motherboard.
The pins look fine, but I think this is almost certainty a hardware issue.

Or maybe a dead bug doing some afterlife conducting.

 

[lantis3]

So I just randomly saw a zip file in my downloads called "Diagnostic_v2.0.7.3_0801_1.zip" and it turned out to be an ethernet diagnostic tool, no idea where it came from but it may have downloaded with one of the drivers I downloaded last week.

I ran it and it tells me I have a short in the 7-8 pair.

So I ran the test with the cable unplugged and the short is still there:

I think this confirms that there's a short somewhere in the pins, or deeper inside the controller/motherboard.
The pins look fine, but I think this is almost certainty a hardware issue.

Or maybe a dead bug doing some afterlife conducting.

I also mentioned this tool in another thread. You probably need a new NIC.

https://forums.tomshardware.com/thr...y-and-drastically-drops.3839437/post-23222920

 

[gijoe50000]

I also mentioned this tool in another thread. You probably need a new NIC.

https://forums.tomshardware.com/thr...y-and-drastically-drops.3839437/post-23222920

Yea, it's really handy, I never even heard of it until I stumbled onto it in my Downloads folder!
I've read a lot of posts about people being stuck at 100mbps but never saw anybody mention it before..