I sit really worth worrying about? Do you have a use case for enabling it? All it is is an endless list of your membership. What is the value to you for enabling it?
Well naturally threads are all seperated by different node and thread ids etc
members list would be just member id, so naturally it would be resource heavy on a single page retrieving them all while all threads would never be all on the same page.
But as noted, this would only be on the members list page, and would really depend on hosts also.