Admin users are getting a really slow page load due to the "Site Administration" menu item in the admin block.
All other user types get a fast page load - e.g less than 1 second.
Admin users are getting a load time in excess of 2 seconds.
If I comment out $admin = $this->load_adminisration_settings() around line 3271 then the page loads quickly.
With Moodle 2.4 the page load is much faster for admin users.