I've been having an issue where my Ethernet connection is stuck at 100 Mbps until I disable and re-enable the Ethernet driver multiple times. Eventually, it recognizes that I have a gigabit connection. I don't need to touch the hardware; just restarting the network adapter does the trick. The cable works fine on other devices, so I'm starting to think the Ethernet port might be faulty and causing some issues with auto-negotiation. Does anyone have suggestions or ideas on what might be going wrong?
5 Answers
Is the Ethernet connection the only one between your PC and the router? If so, trying a different port on the router could help, provided you're sure the cable isn't at fault. If there's anything like an Ethernet wall jack or a switch involved, you might have more points of failure to check.
There are a few things that could be causing this, including a faulty Ethernet port. When a connection is established, the drivers check speed settings and then probe the connection. If they find that the expected speed is not reachable due to frequent dropouts or errors, they may downgrade the speed. This usually points to issues with the ports, cables, or even the wrong type of cable being used.
Are you seeing a setting for 100 Mbps in the network card configurations, or just the overall network speed?
A problematic cable used with marginal hardware can definitely lead to this issue. I recommend trying a different Ethernet cable if possible. Sometimes you can grab one from your internet provider's office, as they often get returns with cables included.
This sounds like an auto-negotiation problem with your network interface card (NIC). Try forcing gigabit speed in the adapter's advanced settings instead of relying on auto-negotiation. If it works after that, your port is likely fine, but the drivers could be flaky.
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