Too many roots?

It happened a lot on runtime that suddenly unity through me an error says "Too many roots" and it crashes. Obviously there is something too heavy on performance that'll cause this. But I wanna know exactly which hardware is under pressure too much. Is it related to memory, process, graphic card or ...? And if you have any suggestions or advise on this matter I would like to hear.

Thanks,

The CPU/processor is usually the one maxing out when this happens. Check your task manager or whatever the mac equivalent of a visual performance monitor is and keep it ontop of all windows then run Unity just to check.