Are you sure it's not showing 100% idle?
The idle process uses up whatever cpu cycles are not being used by anything useful and is shown by 'top -SH' and opn the System Activity page. E.g.:
[2.0.2-RELEASE][root@pfsense.fire.box]/root(2): top -SH
last pid: 58916; load averages: 0.22, 0.08, 0.02 up 2+13:37:03 12:05:18
101 processes: 2 running, 83 sleeping, 16 waiting
CPU: 0.0% user, 0.0% nice, 0.0% system, 0.0% interrupt, 100% idle
Mem: 45M Active, 15M Inact, 66M Wired, 1064K Cache, 59M Buf, 359M Free
Swap:
PID USERNAME PRI NICE SIZE RES STATE TIME WCPU COMMAND
10 root 171 ki31 0K 8K RUN 59.5H 98.00% idle
262 root 76 20 3408K 1224K kqread 9:36 0.00% check_reload_status
11 root -32 - 0K 128K WAIT 8:01 0.00% {swi4: clock}
11 root -68 - 0K 128K WAIT 4:15 0.00% {irq18: em0 ath0+}
A copy of your output will clear this up in seconds.
Steve