CMS Admin User management timeout errors

Description

Steps to reproduce:

1. Create 8000 users with some role set to it.
2. Go to admin view and click on "Administer Groups".
3. Click on the role which the 8000 users belong to.

Expected result:

The view should load up quickly.

Actual result:

Loads every user instead of taking some at a time, which causes the loading of the view to take a long time or to time out.