Will ScheduleStepJobs ever require fewer Completes? Scheduling large numbers of PhysicsWorlds to update simulatenously has like, 50% idle time. Edit: Oh, interesting, I wrote a custom Simulation implementation that lets me batch the sections that require Completes, but there's still about the same amount of idle time. Alas. Double Edit: The completes are still the problem, though. 75% of my frame time is being spent in broadphase/pair generation, with really poor thread utilization during that time. Even with the various world data gathering jobs scheduled and completed as a group. Triple Edit: If I'm maintaining multiple worlds and have to sequentially update each one multiple times (i.e., run PhysicsWorldA-Iteration1, PhysicsWorldB-Iteration1 together, then followed with PhysicsWorldA-Iteration2, PhysicsWorldB-Iteration2) the required .Complete calls make this even worse.