I am trying to understand what factors impact the performance of a criteria based group. I have read that member size has direct impact, but it does not make much sense, When a resource is updated, FIM looks for all criteria based groups that have criteria containing the attributes updated in the resource and recalculates the membership of those groups. So my understanding is that the performance of criteria based group is dependent on the criteria, not on the member size of the group. If you have a lot of criteria, then FIM will spend more time on evaluating the criteria and the chance of matching the attribute with the attributes updated in a resource will increase. The member size should not have much impact here.
Yes, member size can be an issue, but that will not be limited to a criteria based group - that should apply to any groups with large number of members. Because that impacts the memory footprints and complexity of membership calculation both in Sync and in AD.
Is my understanding correct, or I am missing something?