Sluggish WiFi after playing video on Kodi on Pi 3B

[draylin]

Hello everyone,

I stumbled across an very strange issue with my setup. I use my Pi as a kind of WiFi repeater, utilizing a Netis USB WiFi adapter with the rtl8812au chipset as the WiFi client and the integrated WiFi in AP mode. In addition I am using it as a media center with Kodi, therefore it is running the Pi2 image for GPU accelleration.

The whole WiFi thing works pretty well until I start to play a video on Kodi using the YouTube addon. As soon as the video starts the WiFi performance (of the Internet connection via the Netis adapter) massively degrades and the connection becomes too slow to smoothly play back the video. The decline of throughput and latency is also noticeable by the clients in the AP network. To restore the connection quality I have to restart my Pi.

CPU temperature while video playback is about 55c, power save features of the WiFi adapters are disabled and all WiFi networks use different channels. I have no issues playing the same videos with the same quality on devices within the AP network.