One minute it's .812 second, the next it's 203 seconds. It's about a 50-50 split. I have 1GB reserved for MySQL in my.cnf, otherwise it's stock MySQL 5.7.
SELECT ug.user_id, a.forum_id, r.auth_setting, r.auth_option_id, ao.auth_option
FROM phpbb_acl_groups a, phpbb_user_group ug, phpbb_groups...