Physics: why do a few cubes simulate ok, but many cause themselves to jitter forever?

Hey, I was just simulating dice throws (into a walled off area) for fun and I noticed that 3-4 were fine but anything above caused them all to jitter non-stop. And it seemed that it was when they came into a certain proximity to each other, definitely no direct interactions.

So I turned up the sleep number and now they jitter less but tend to glide on the ground without stopping.

Does anyone have any insight as to what’s going on with the jittering and how to solve it?

Thanks!

(on the answers forum in case you want karma:
https://answers.unrealengine.com/questions/387378/dice-physics-experiment-why-do-many-cause-jitters.html )

babygotbump

Perhaps they are too light. Do you use box collision on them or a custom mesh? Try to app position and velocity iterations too.