We are using standart UFS file system but IO is not the problem.
This is strange the CPU user == system. With apache22 with mod_fcgid we have round 20-25% idle and the system load is very low.

last pid: 25961; load averages: 48.43, 34.30, 36.86 up 5+00:02:08 23:45:08
184 processes: 69 running, 114 sleeping, 1 lock
CPU: 52.5% user, 0.0% nice, 47.5% system, 0.0% interrupt, 0.0% idle
Mem: 1786M Active, 4256M Inact, 1256M Wired, 213M Cache, 828M Buf, 407M Free
Swap: 4096M Total, 92K Used, 4096M Free