2 tables in mysql database overloading cpu even after optimize

thanks for reading this question i hope someone can give some insight into some steps. Here is my steps report. I added memcached instead of mysql cache. optimize the 2 tables from buddypress that where making the mysql overload. But still the problem is there. Not sure what the step might be next? Any guide into this would be much appreciated Table 1 structure wp. SELECT DISTINCT g.id, g.*, gm1.meta_value AS total_member_count, gm2.meta_value AS last_activity FROM b9t_bp_groups_groupmeta gm1, b9t_bp_groups_groupmeta gm2, b9t_bp_groups g WHERE g.id = gm1.group_id AND g.id = gm2.group_id AND gm2.meta_key = 'last_activity' AND gm1.meta_key = 'total_member_count' AND g.status != 'hidden' ORDER BY last_activity DESC LIMIT 0, 20 Server: Localhost via UNIX socket Server type: Percona Server Server version: 5.5.33-31.1-log - Percona Server (GPL), Release rel31.1, Revision 566 Protocol version: 10 cpsrvd 11.42.1.16 Database client version: libmysql - 5.0.96 PHP extension: mysqli bp_groups InnoDB 10 Compact 15191 7703 117030912 0 6979584 5242880 14555 2014-06-12 11:39:33 NULL NULL utf8_general_ci NULL bp_groups_groupmeta InnoDB 10 Compact 30487 86 2637824 0 7946240 4194304 32376 2014-06-12 11:59:52 NULL NULL utf8_general_ci NULL