please help me make sense of top's CPU output

[Chris Stankevitz]

Hello,

I recently performed a CPU intensive task with Xorg.  When I completed the task and Xorg no longer was using the CPU, I got this result from top:

===

last pid:  1201;  load averages:  0.24,  0.10,  0.09    up 0+00:29:42
63 processes:  1 running, 62 sleeping
CPU:  1.0% user,  0.0% nice,  0.0% system,  0.0% interrupt, 99.0% idle
Mem: 161M Active, 67M Inact, 68M Wired, 1240K Cache, 41M Buf, 1676M Free
Swap: 4060M Total, 4060M Free

  PID USERNAME     THR PRI NICE   SIZE    RES STATE  C   TIME    CPU
 1017 cstankevitz    1 104    0   366M   331M select 0   3:25 35.89% Xorg

===

Note that the "CPU" row reports 99% idle.
Note that the "CPU" column reports 36% Xorg

I have two questions:

1. Why do these two numbers seem to not agree?  One reports the CPU is not being used, the other reports Xorg is using the CPU.

2. How can I change my system so that these two numbers seem to agree?

Thank you,

Chris

PS: conky does the same thing -- I assume this means the seemingly disagreeing numbers are coming from the FreeBSD kernel.