Maybe you should read my comment again? It's that ThreeJS abstraction library that's slow and why it's not okay to say it's a WebGL demo, it's a Three.js demo.

Maybe you should read my comment again? It's that ThreeJS abstraction library that's slow and why it's not okay to say it's a WebGL demo, it's a Three.js demo. As you can see with comments above people blame it to WebGL is slow - which is simply incorrect as WebGL is based on OpenGL ES 2.0 and exposed as HTML5 API. If you hand tune the JS and shader code WebGL can be very fast and short startup time. You won't get that benefits from generic fat libraries.