Network connection dropping to 1gbps

Sometime in the past month, The connection to my 2.5gb switch keeps getting stuck at 1gbps.

I have to go and unplug the network cable from the switch or my PC and plug it back in again to get a 2.5gb link back. Sometimes it takes multiple tries.

I have no idea why this is happening. I have tried updating the NIC drivers in Windows as it was using a old M$ driver from the dark ages.

I have tried setting the NIC to use 2.5Gb full duplex but that's not got it either. Just disabling the NIC in windows and enabling it again does not work. I have to physicly remove the cable.

Once it is back to a 2.5gb link the connection seems perfectly stable.

Any ideas what the issue might be?

The other devices connected to my switch all stay at 2.5gb.. but then again they dont get turned off at the end of my day, My PC does.

Looks to me like the behaviour I would expect if your cable arrangement was a bit marginal for 2.5Gb/s, although that might not be the cause.

You've probably tried this but here's a couple of elimination steps.

Step 1 is to swap the cable with another device but keep using the same switch port for this PC.
Then wait and see if the problem stays with the PC or now affects the device with that cable.

Step 2 step is to swap the switch port used by the PC with another device.
Then wait see whether the problem stays on the same switch port and affects another device, or remains with the PC.

If the problem remains with the PC then it is not the cable nor port, and It's possible that the NIC/driver does not properly handle the sleep / wake up cycles. After a reboot of the PC does it always come up at 2.5G without exception?

Rule 2 of comms applies : it's always the cable

In reply to a post by prlzx:

After a reboot of the PC does it always come up at 2.5G without exception?

No, It will not come back with a reboot or when the PC has been off. I HAVE to re-plug the cable every time.

I cant swap the cable right now as the rest of the cables I use are only short ones and the one to my PC is 3 meters long.

Cables are not expensive so come payday I think Ill just have to grab a new CAT6e

Has something enabled EEE on the switch? This was a big issue on the VM Hub 5 and dropped it's 2.5Gb port to 1Gb. The solution was to switch off EEE on the managed switch.

Cat 6E isn't a thing. Cat 5e, Cat 6 or Cat 6A are all fine for 2.5G

Out of interest does it matter what end of the cable you re-plug to get it back to 2.5G?

Thats true, The cable says it is tho

Yes.

I have to unplug it from the switch and connect it to another port and it will go back to 2.5gb

If i then plug it back into the port it was in at 1gb it will now be 2.5gb.

If I unplug it from the PC end it makes no difference.