No idea, sorry. My guess is that it's the JS VM but I don't know how to check. I just tried running a profile, but Safari froze and beach-balled to death. When

No idea, sorry. My guess is that it's the JS VM but I don't know how to check. I just tried running a profile, but Safari froze and beach-balled to death. When I do profiles in Chrome it drops from 60fps down to 45. :/ Fortunately for me, Safari also doesn't implement some HTML5 APIs I use (e.g. PointerLock), so I feel justified in pretending it doesn't exist.