Here is the result:
http://pastebin.com/3byhmhNV
PS. 8 CPU'S
Cpu0 : 18.2%us, 3.3%sy, 0.0%ni, 78.5%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
Cpu1 : 12.3%us, 3.7%sy, 0.0%ni, 83.7%id, 0.0%wa, 0.0%hi, 0.3%si, 0.0%st
Cpu2 : 8.6%us, 3.7%sy, 0.0%ni, 86.7%id, 0.0%wa, 0.0%hi, 1.0%si, 0.0%st
Cpu3 : 15.9%us, 5.0%sy, 0.0%ni, 78.5%id, 0.0%wa, 0.0%hi, 0.7%si, 0.0%st
Cpu4 : 0.3%us, 0.0%sy, 0.0%ni, 99.7%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
Cpu5 : 0.3%us, 0.3%sy, 0.0%ni, 99.3%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
Cpu6 : 1.0%us, 1.0%sy, 0.0%ni, 98.0%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
Cpu7 : 0.7%us, 0.0%sy, 0.0%ni, 99.3%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
Increasing MaxClients will not help at all, it will put more stress on the server than it's already experiencing. You have a ton of slow MySQL queries. Enable the slow query log to identifiy the slow queries and fix them.
Enable Slow Query log
Make the log file
touch /var/lib/mysql/slow_query.log
Open my.cnf file. Likely in /etc/my.cnf
Add the following line to the [mysqld] section
log-slow-queries = /var/lib/mysql/slow_query.log
Now restart mysql
service mysql restart
or
/etc/init.d/mysql restart
Also, how many CPU's does this server have? Run top then press 1 to find out. Or cat /proc/cpuinfo
Also, what's the output from free -m?