I don't know really what is the problem but I have results that I can't explain.
Maybe I just understand nothing of how this should works.

My test graph his 20 3D chunks

When I use a task limit of 1 it's took 2000ms to generate all chunks.
When I use a task limit of 20 it's took 4300ms to generate all chunks.

I am using the .queue method to add all tasks to the pool

@cullumi do you have any ideas ?