mySQL: Insert грузит CPU до 30-35%

[client]
#password<----->= your_password
port<--><------>= 3306
socket<><------>= /tmp/mysql.sock
default-character-set = utf8

# Here follows entries for some specific programs

# The MySQL server
[mysqld]
port<--><------>= 3306
socket<><------>= /tmp/mysql.sock
skip-locking
skip-innodb
key_buffer_size = 16M
max_allowed_packet = 1M
table_open_cache = 8
sort_buffer_size = 64M
read_buffer_size = 256M
read_rnd_buffer_size = 256M
net_buffer_length = 2M
thread_stack = 128M

query_cache_limit=1M
query_cache_size=64M
query_cache_type=1

max_connections=50000

interactive_timeout=1
wait_timeout=1
connect_timeout=1

thread_cache_size=64
key_buffer=8k
join_buffer=1M
max_allowed_packet=32M
table_cache=256M
record_buffer=1M
sort_buffer_size=2M
record_buffer=1M
sort_buffer_size=2M
read_buffer_size=2M
read_rnd_buffer_size=768k
max_connect_errors=10
thread_concurrency=4
myisam_sort_buffer_size=64M

#skip-networking
server-id<----->= 1
default-character-set = utf8

# Uncomment the following if you want to log updates
#log-bin=mysql-bin

# binary logging format - mixed recommended
#binlog_format=mixed

# Uncomment the following if you are using InnoDB tables
#innodb_data_home_dir = /var/db/mysql/
#innodb_data_file_path = ibdata1:10M:autoextend
#innodb_log_group_home_dir = /var/db/mysql/
# You can set .._buffer_pool_size up to 50 - 80 %
# of RAM but beware of setting memory usage too high
#innodb_buffer_pool_size = 16M
#innodb_additional_mem_pool_size = 2M
# Set .._log_file_size to 25 % of buffer pool size
#innodb_log_file_size = 5M
#innodb_log_buffer_size = 8M
#innodb_flush_log_at_trx_commit = 1
#innodb_lock_wait_timeout = 50

[mysqldump]
quick
max_allowed_packet = 16M
default-character-set = utf8

[mysql]
no-auto-rehash
# Remove the next comment character if you are not familiar with SQL
#safe-updates

default-character-set = utf8
[myisamchk]
key_buffer_size = 64M
sort_buffer_size = 64M

[mysqlhotcopy]
interactive-timeout