8:49am up 1 day, 18:34, 2 users, load average: 3.37, 3.55, 3.45
143 processes: 133 sleeping, 6 running, 4 zombie, 0 stopped
CPU states: 53.8% user, 36.0% system, 10.2% nice, 0.0% idle
Mem: 514152K av, 507520K used, 6632K free, 0K shrd, 26136K buff
Swap: 264952K av, 145344K used, 119608K free 366428K cached
It's busy !
Try
top -i
to show just the processes that are actually running at the moment, that will give a clue as to what your server is doing (and perhaps why it is going slow).