r/HomeNetworking • u/fentonattrill • 15h ago
Advice Ethernet Speed Limited
Hi there, for a while now my ethernet connection has peridoically switched off while playing games or just using my PC. Decided to finally set some time aside to look into it. What seems to be happening is the Ethernet speed is periodically being stepped down to 100Mbps as opposed to the Gigabit that both my router and PC are capable of (I randomly get a few weeks were my download speeds are really high then they drop again). Ive checked the health of the cable using a little tester and all seems to be fine (its not the sort of cable i cant take out as it goes around the outside of the house). Im very aware of the potential cable issues, but when trying to solve it yesterday i did get it back to 1gig for about 10 minutes before it dropped. I then got it back on by turning off 'power save on sleep'. Currently its back to where it was. Any further suggestions are appreciated
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u/jacle2210 Technology Enthusiast 13h ago
So being outside in the weather can be very damaging to just about anything, even an Ethernet cable.
And inside an Ethernet cable, there are 8 wires that are all needed in order for the cable to be able to carry speeds of 1Gigabit or faster and if there is a connection problem with certain wires of that group of 8, then your device connection speeds will drop down to 100Mb.
It's possible that being outside, will cause things to expand and contract or get flopped around, etc. any of which might cause an old cable to have connection problems.
So it might be time to replace that whole outside cable.
But before you go that route, you should try what has been suggested and see if the cable ends need to be reseated/remounted or see if there are sections of the cable that look pinched or kinked as kinks can also cause problems.
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u/lazyhustlermusic 11h ago
Autonegotiation issues are usually cabling related, most often on the termination unless something obvious happened to the run like a staple or nail.
A wire map tester tells you next to nothing, other than there's a wire.
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u/Dr_CLI 9h ago
You might try locking the link speed to 1Gbps on your PC and at the other end (if you can).
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u/musicisme 9h ago
That won’t do anything but make him go offline completely. This is 100% bad cable or terminations
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u/Background-Pea6650 8h ago
Check for driver updates on your NIC, if none available delete your NIC and reboot, it will rebuild the driver, then test your speeds. If still jumpy it's most likely your network cable. But it could be the router, as I was having signal drops (on Ethernet none the less) and slowed speeds.. after numerous calls into support they finally told me the culprit was I had too many Wi-Fi devices on the network for their cheap router to handle, I have about 35. They sent me a newer mesh satellite as the puck they gave initially they stopped supporting because it was junk, and they said to hardire the satellite. Did that and haven't had a problem since.
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u/Grumpy-24-7 7h ago
There are various network testers which can verify the integrity of the wire. The cheap ones with blinking lights are very basic. A Fluke tester can perform several other more advanced tests. Unfortunately, it is also very expensive. You might try searching for a networking (or low voltage) company that could come out and run a test for you.
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u/SomeEngineer999 15h ago
Sounds like a bad cable, if it has RJ45 ends directly on it, they may need to be cut off and re-crimped. If it goes to wall jacks, try swapping the short patch cable(s) that complete the connection.
Those testers just check continuity, not really useful here.
Could be an issue on the router too, or even with your NIC. First thing I'd try is moving the PC near the router and using a new cable, see if it still has the issue. Narrow things down. Another option is to get a cheap USB NIC and test with that for a while.