For the last few months, my desktop computer's internet speed became somewhat unstable (ethernet connection). I thought it was an OS issue (Windows 10), but turned out it was the same on my dual-boot Ubuntu 18.04 too.
It happens occasionally and lasts for a few hours. On Ubuntu, the network icon would have a question mark on it
On Windows, the internet speed becomes incredibly slow or display network disconnected icon sometimes
And when I plug off the ethernet cable and plug it into my laptop, everything is fine.
Do I have to replace the whole motherboard? Or is it only the network interface issue?