You CPU load is not high, it's only 4%. Load average (5min) is a bit high, but not abnormal.
try shell commands:
it shows realtime values. quit with q. Press s +2 to set 2 second sampling interval.
It'll show all processes and what is running them.
free -t -m
shows you memory usage in MB:s. Normally nearly all memory should be used in Linux, but swap only by a little amount (2-5% of swap size). If you're swapping a lot it will kill performance.
It's hard to say anything specific as we don't know what scripts, databases, traffic do you run, and how.
Last edited by PSS; 01-20-2009 at 12:06 PM..