This is a longshot - is there anyway to detect poor vs strong graphics card performance via a JS plugin?
We have built a parallax site for a client, it stutters on lower
requestAnimationFrame (rAF) can help with this.
You could figure out your framerate using rAF. Details about that here: calculate FPS in Canvas using requestAnimationFrame. In short, you figure out the time difference between frames then divide 1 by it (e.g. 1/.0159s ~= 62fps ).
Note: with any method you choose, performance will be arbitrarily decided. Perhaps anything over 24 frames per second could be considered "high performance."