Question PC only accept some network cables

Dec 6, 2022
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My PC only accepts one of my network cables. All cables work between other equipment (router, swith, etc.). The one not working happens to be cat 5, all the others are cat5e.

My motherboard is a MSI pro Z690, bought this year.

Is the motherboard faulty, or could there be another explanaion?
 
It is not likely the port but I guess it could be. I assume you mean the port does not come up at all rather than it does something like run slow or get errors ?

It would be highly unlikely you have a actual cat5 cable. It would likely be over 10yrs old they pretty much moved everything to cat5e years ago.

What I suspect is some of the cables you have are not actually ethernet cables....or more they do not meet the standards to function as ethernet cables. The most common kind are those flat cables that have wires far too small to meet the standards.

2.5g ports in general seem to be much less tolerant of a cable that is out of spec. Even perfectly good cable can get damaged. All it takes is to crack a wire internal to the rj45 plug and it will then not pass traffic they way it is suppose to. I had one that had a tiny spec of damaged plastic that was blocking one of the pins but you could only see it with a magnifier.
 
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Dec 6, 2022
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Your assumption are correct, the connection is not detected at all.

It is really a cat5 cable. When my regular CAT5e cable didn't work I assumed it was broken and changes to another. Then again and again, until I dug deep enough is my old network-junk and found the now working cat5 cable. I later tested all the cat5e cables on other equipment since it seemed unlikely that suddenly all of them were broken.

Some of the cables are probably not up to the cat5e standard. Though they do work on other equipment. A couple of them, I have terminated myself with a bit more expensive cable type (still cat5e).
If 2.5g ports is less tolerant they should not accept an old cat5 cable.

I'll try updating the driver, I saw yesterday there was a release in november.
If that doesn't work maybe I will dig up some other cat53 cables to test them.
If there's still no luck I will contact MSI.
 
The cable detection and speed are something done by voltage levels etc. It is not really something that is done firmware or drivers. It is something that is built into the chips when they are manufactured.
Most times when it is a driver issue they do not work at all with any cables.

If you think it is a driver issue you can try a linux USB boot image. Most those support that 2.5 chipset now. It would quickly eliminate or blame microsoft as the cause.

I guess it could be a bad port but that is very rare and really the only option is to RMA the whole motherboard which is a massive pain. If that is the case a PCIE or USB3 add in card will be the quickest solution and they are fairly inexpensive.
 
Reactions: Dark Lord of Tech

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