This is an i7 4500U, Intel HD 4400 (Intel Graphics Family). Drops approximately 5% of the frames resulting in video stutter. Running on a (tested) 200mbps connection. Like I said in the title, Edge plays fine. I remember a few versions ago (can't pinpoint now), Firefox used to play theses videos without any issues. Examples: https://www.youtube.com/watch?v=79ImZE0K7xc And https://www.youtube.com/watch?v=IeZeINA1ts0 I spent the last morning trying every solution I found on the Internet, Reddit and Mozilla forums. Disabling stuff in the about:config, webgl stuff, doublebuffer, etc, etc. Tried downgrading to V77, disabling enabling 3D acc., etc. Thanks.