I don't know what causes this but i will describe what is seen when the issue is caused: 1) Be on a stream on twitch.tv 2) Open Elder Scrolls Online(Borderless Windowed, so no exclusive mode) for a while. 3) Alt-tab out, go to Twitch.tv. For some reason something causes the video on twitch.tv to rubberbanding, in a really weird way: The video actually seems to repeat a previously cached frame during playback, causing weird rubberbanding, even though the video itself seems to play fine apart from wrong frames being inserted. Refreshing the video player or the page fixes the issue(likely because of cleared video cache. This issue is not on Google Chrome, and this is the main reason i can't make the switch to Firefox I'm going to give a guess that the Twitch.tv HTML5 video buffering is somehow borked on Firefox, and it seems to have to do with DirectX, as it only really happens when i've played a game.