What’s the browser you’re using ? and also please do:
glxinfo|egrep -i "^direct"
You’re looking for a line that says “direct rendering”; specifically whether or not it says “yes”. This will help pinpoint if you’re actually using your GPU or some onboard chipset instead.
With that being said, even assuming you use the latter, stuttering video playback in the browser is weird; if using firefox, out of curiosity: try to disable or enable hardware rendering (options > advanced > general), and try again. Switch it back to what it was when your test is done.
With the state of Javascript being what it is, you probably can chain syllables randomly and have a fair chance of the resulting word being the name of a temporarily-existing framework