Speed ​​change from 1Gb/s to 100Mb/s?

Question

Computer networks

There is a computer with a gigabit card, a patch goes from it to the network socket, from the socket to the patch panel, from there to the switch and plugged into the gigabit port.
The problem is that the speed of some fig drops from gigabit to 100mb / s, and not immediately, but approximately 2-3 days after I plug the cable into the network card.
Setevukha put new - did not help.
In the settings there was both auto-negotiation and full duplex 1gb / s, and no matter what I set, it still slows down after a while.
If you believe the switch, indications, then this port works on gigabit. It turns out that the speed cuts either the patch cord itself, or Windows.
From the computer to the closet 20 meters of cable.
Tell me where to dig? And point me in the right direction.
Thanks to.

Answer 1

What are you doing to restore gigabit?
Problems can be on any site between a computer and a switch:
1. the switch/port in a switch dies or is buggy;
2. computer's network adapter (but you already changed it to another one, so this is probably not it)
3. bad contact in one of the patch cords, connectors, sockets
4. network adapter driver curves.
What can be done: 1. Find
the latest drivers for the network adapter and reinstall
2. Replace the patch cords that you can.
3.Peretknit to another port on the switch, or better - to another switch.
4. Use a different outlet to connect your computer
As an experiment: plug this computer directly into the switch with one cable (so that there are no extra joints, this way you check the cable from the socket to the patch panel); plug another computer into this switch port that did not have such a problem before.
Perhaps the results of these actions will help to identify the cause of the problem.

Answer 2

Definitely a bad connection. Perhaps this is periodically (weather, somewhere not very good contact), and the speed drops to a lower one at the first re- "negotiation".
You can put 1 GB in the card instead of Auto Negotiation.
PS Did you check the real download speed? Does it get to gigabit?

Answer 3

There was a similar problem, only not after 2-3 days, but about once a day, randomly. It turned out that one of the 4 pairs in the socket was turned upside down when driving ... PPC ..))) I tried the socket and everything was chocolate. So the advice about direct switching is the most adequate, then in pieces to identify the problematic part of the route ...
Well, do not forget about Aunt Manya, the cleaning lady. By the way, do you have cleaning service more than once every 3 days?)))

Answer 4

In the settings of the network card, there are no items (GreeEthernet, power saving and / or the like)!?
Are 4 pairs embroidered at all stages? Check with a tester.

Answer 5

Bad cable/connectors