I have connected an Ethernet cable to my Chromebook and to my router but still receive messages indicating that my internet is unstable enough to run Stadia. My internet download speed tested at 28.486 Mbps which I believe is good enough to run Stadia. Is there a setting that needs to be changed when connecting an ethernet cable to a Chromebook? Something else that I need to do in order to play Stadia?
maybe there are some other bandwidth consumers on your privat network? Does your Chromebook synchronize files which "pirates" some bandwith?
You can check your internet connection (related to Stadia) with e.g. this speed test https://projectstream.google.com/speedtest.
I had the same issues that you did. Great connection, however I would lose connection for what seemed like no reason. I did a bit of research and found out that my Chromebook was running a legacy decoder for visuals h264. Google has switched over to a V9 decoder. This excerpt is from Wikipedia:
VP9 is the successor to VP8 and competes mainly with MPEG's High Efficiency Video Coding (HEVC/H.265). At first, VP9 was mainly used on Google's video platform YouTube. The emergence of the Alliance for Open Media, and its support for the ongoing development of the successor AV1, of which Google is a part, led to growing interest in the format.
I'll let you finish the equation for what you might need to do from here. I hope this helped.