You can even on this old XP box grab the vlc player window and drag it all over screen violently and it doesn't cause a stutter. But my VLC player is set to hardware acceleration and plays 1080p h.264 encoded mk4/mp4 smooth as silk. I googled about loss of h.264 hardware acceleration since flash and html5 both couldn't play hd content.

I saw that in the troubleshooting information that now it was reporting that h.264 hardware decoding was now showing not supported.

The the video would play a couple moments then choke/freeze/stutter. I also went to vimeo/twitch/dailymotion and flashplayer autoload but the hd content struggled to play it did very similar to youtube freezing on html5. Chris gave me a workaround in about:config to force html5 player to load, and it did but it too was choppy, the browser would play a couple seconds and freeze, which would lock everything up, I say that because moving mouse to stop the playback or close tab the mouse cursor froze on screen until the video would play a couple more seconds. I noticed hd content in flash was choppy. When I upgraded to 43.0.4 I noticed html5 would not load at all on youtube and I had to reinstall flash. For record I do not have hardware acceleration anymore in h.264/flash content.

How to fix vp9 display vlc media player