MySQL using too much CPU

I'm studying to be a DBA right now because I have a massive live database that is very sensitive that I manage. Here's the current system stats of my dedicated database server: - CentOS 5.9 - 24gb Ram - 8 Core CPU - 50gb FusionIO disk for /var/lib/mysql - MySQL 5.5.23 top - 18:40:27 up 14 days, 4:43, 1 user, load average: 19.72, 22.62, 24.04 Tasks: 183 total, 3 running, 180 sleeping, 0 stopped, 0 zombie Cpu(s): 69.9%us, 0.4%sy, 0.0%ni, 29.2%id, 0.0%wa, 0.1%hi, 0.4%si, 0.0%st Mem: 24685224k total, 20172096k used, 4513128k free, 343420k buffers Swap: 2007284k total, 0k used, 2007284k free, 729004k cached PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 5446 mysql 15 0 18.4g 17g 6176 R 765.8 76.2 114437:38 mysqld I'm currently using 43gb of that 50gb FusionIO slice. MySQL averages around 700 QPS and 75-90% CPU usage. Here's my my.cnf file: [mysqld] user=mysql datadir=/var/lib/mysql socket=/var/lib/mysql/mysql.sock #innodb #innodb_log_file_size = 256M #innodb_log_buffer_size = 8M innodb_flush_log_at_trx_commit = 2 innodb_lock_wait_timeout=50 innodb_file_per_table innodb_buffer_pool_size=16G innodb_buffer_pool_instances=4 #eliminating double buffering innodb_flush_method = O_DIRECT flush_time=86400 skip-name-resolve query_cache_limit=4M query_cache_size=256M sort_buffer_size=8M read_rnd_buffer_size=1M max_connections=5000 interactive_timeout=60 wait_timeout=300 connect_timeout=30 thread_cache_size=32 key_buffer=124M tmp_table_size=4096M max_heap_table_size=256M join_buffer=16M max_connect_errors=2000 table_cache=2048 thread_concurrency=12 long_query_time=5 log-slow-queries=/var/log/mysql-slow.log #table_definition_cache=384 max_allowed_packet=1024M #server-id=20 #log-bin=mysql-bin #expire_logs_days=10 event_scheduler=ON [mysqld_safe] log-error=/var/log/mysqld.log pid-file=/var/run/mysqld/mysqld.pid can you guys recommend any config changes I should make to MySQL or CentOS that can greatly reduce my CPU usage? Or for that matter any other resource improvements?