I have my xbox directly wired to router, but my pic is wireless.. its also 2 feet from the router. I can stream on the max quality without any input lag at all. Infact, ive got the xbox on hdmi cable with one monitor, win10 on the other... so i actually watch the xbox feed when im playing.
Hmm... thats good to know, Again, I've only tried it with 2 routers, one is pretty old, and the other is decently newer. Its also worth noting, if you are going to be playing over your actual network, you will notice a big hit in performance, and that goes across your whole network. Having the stream quality set at very high settings will have your router transferring close, or over a hundred gb of data from your pc to xbox, and thats only with about 3-5 hours of gameplay. You can confirm this by checking your bandwith usage in the Xbox One Network settings.
Also, you say your able to watch the Xbox Feed on the Windows 10 PC?, this means your not using the Windows 10 Stream as your main display to play correct? Your essentially playing on the main xbox one screen, and watching the Xbox One Stream on the monitor next to it.
I would not expect much input/feed lag when you are playing on the main Xbox One Display, although, if you were to actually play with the Windows 10 stream, and not the original Xbox One display. You should definitely notice a bit of stuttering, and lag, when you are playing on the very high streaming settings. Its even more pronounced if you turn on the DVR and record at the highest settings, and have background recording enabled. The input/feedback lag is not with the Xim3 it self. Its just general lag with stream,, that will make the Xim3 unusable, but this is why I my self play with my Xbox Ones original Display, not the Windows 10 Stream.
Its nice to have the stream on very high, because you can record up to 2 hours of gameplay. Its just not possible to try and use the windows 10 Streaming window to actually play. You need to play on the Xbox One Original Display.