I have an ethernet cable (cat5e), connecting my PC and router through an on board ethernet port. My ISP data speed is 120Mbps/120Mbps Down/Up.
Testing through www.speedtest.net I get exactly above speeds since the beginning of the test. No problems at all. Tried that many times and I always get maximum of my speed.
After a couple of hours (eg. 10 hours later) I retest my internet connection. This time downlink is 120Mbps but uplink seems to fluctuate, starting from 10-25 to 70Mbps. No matter how many times I do the test uplink seems to be unstable. Even If I restart PC the problem remains.
This time I instantly plug the ethernet cable out and put it back in, connection re-establish in 1-2 sec, and this time uplink is OK. Full 120/120 both down/up. No fluctuations at all. After many hours uplink again become unstable.
Any ideas on what might cause that behavior?
- Bad ethernet cable?
- Bad ethernet onboard card?
- Problem with drivers?
- Router problem?
- Windows 10 problem?
It was the cable... Badly connected to plug. No fluctuations anymore