BTW guys, some tips:
- Make sure to turn off dynamic shadows for most things
- Turn off collisions between static actors
- Turn off gravity for static actors.
- Make any non-moving level geometry static (not movable).
- Reduce the number of lights that cast shadows.
- Keep GPU particles to a minimum, or use lowest LODs for GPU particles, and no scene collision.
- Use no more than one particle light node.
I was able to get my juddering mess of a demo to run perfectly smooth.