Strange CPU Activity?!

Hey,

MacBook 1,83GHz - 2GB RAM



As you can see, no process shows any activity, but the CPU shows ~50%. Where does this come from?

When I reboot it's gone, but some time later it appears magically again. First I thought it's FrontRow, but when I avoided to start use it via the remote, the CPU activity came nevertheless.

It doesn't bother that much, but I do notice that Mail needs somewhat longer to open a new window, which isn't the case when the machine freshly started.

My only open apps are Mail, Firefox, Adium and iTunes (not playing).

 

Great command, thanks.

Now I got this: