Jack, you are almost right about the video card problem, because in the past, I tried to view some demo samples of Babylon.js in Chrome browser ( they worked great ), but they did not work at all in Firefox ( since FF had only partial support for WebGL - http://caniuse.com/#search=webgl )
Now in GSAP's case it's seems to be the other way around... ( partially supported in Chrome while works flawlessly in FF ) though I am not sure of the specifics of the reason behind ...
I use Win XP SP3.