Over the past week or so I have had a huge decrease in playability when trying to use my Steam Link with the Steam Controllers. I have tested with 1-4 controllers plugged in and whenever any input is detected from the controllers I get huge lag spikes every 1 second making gameplay on anything unusable. As far as I'm aware nothing has changed in my setup. My PC and router are upstairs, the Link is downstairs and plugged into my projector. The WiFi signal strength is a solid 3 bars and tests on the Link say it has a good connection speed. I did get a new router a few months ago but I am certain that I have played fine since then and it is only recently that I've started getting the spikes.

The standard overlay shows the red WiFi icon each time it spikes and the detailed overlay graph shows the blue and cyan lines as fine but the red line has the huge spikes - usually from a base level of around 80 to well over twice as high. I'm not sure what the different colour lines mean?

I have tried switching hardware encoding off and on, I have tried setting stream performance to fast, I have tried setting WiFi to only use 5GHz and none have made any difference. I have tried all four controllers plugged directly into my PC and they're all fine, firmware updated etc (though only the controllers - I can't figure out how to update the dongles).