We're working hard on performance in the upcoming updates, so hopefully we'll be seeing a lot of improvement there. We recently discovered a bug in how we do our timestepping that has been fixed, so that should help a good bit, especially on computers that struggle to maintain 60fps.
If you've completed those performance tests, please send in a feedback email with AttenC7 in the subject, so I can review them and see where the slowdowns are happening. Even though I suspect it's something we've already seen, I'd like to make sure you're not having another issue.