I'm not sure if this will work for anyone else, but I just got an update for my Chrome browser so I installed it and was like what the heck I'll try Stadia on Chrome. I'm now getting an excellent connection instead of I always used to get good connection and wouldn't you know it, I also am now officially running 4K HDR in Chrome! My display is a 43" 4K HDR Samsung Smart TV in case anyone's interested.
Edit: I jumped the gun when making this post. There is no "official" HDR for Stadia on Chrome yet.
I can't stream at 4k over Chrome. Can anyone advise?
Running on a Win 10 Surfacebook 2 with Nvidia GTX 1060 (VP9 capable, confirmed)
50mbps wired connection
Connected to a LG 4k 60hz display via Display port
I get 60fps but in all games, only get 1280x720. Tried Stadia+ with no joy.
(4k HDR 5.1 works perfectly via my CCU)
Have you set the connection quality to best quality visuals under data usage and performance in the stadia app? Also you can only get 4K if you're a pro member. I'm not sure if you are or not. Also, have you tried updating your Chrome browser?