Though this topic is quite old, I would like to point out that everyone saying 100% CPU system idle process is normal...is CORRECT. With the task manager list, higher numbers could possibly indicate slower functioning. However, system idle process CPU means something different due to its nature, as others have already explained. This does not make sense to some, and I feel compelled to encourage people to ignore the negative voting scores on these entries; and kindly overlook system idle when searching for explanations of slow computers or programs. System Idle Process is not the culprit.
Haha! Nice! But some people need it
Glad to see you have a sense of humor!