ksysguard cpu meanings
 

What is cpu sys/user/nice

I am guessing that sys is cpu load by the system, and user is user cpu load.

But what is "nice"?

thread scheduling priority.
nice 19 gets along well with others and is willing to yeild it's turn at the cpu and hold the door for orphans
nice -20 or maximum not nice thinks it's more important that everybody else and is horribly self centered