Question: What controls the limits of how many actions can be executed simultaneously?

Hi adambeltz,
In your example with your CPU setup you can use following project structure to tweak parallel execution (see attached project, you have to replace “Wait” actions with actions you want to execute in parallel).
But keep in mind that parallel execution is internal mechanism that may be (and most certainly will be) changed in future.ParallelExecution.morph (7.3 KB)