Ok, it might be stupid... but actually I founded the processes list and checking it on Mint / System monitor. Those 60% of usage is gnome-system-monitor Gosh this is Athlon XP 2800+!

60% is a peak when moving cursor around. If not going down to 40%. It can be a driver problem?

EDIT:
OK I turned "Enable smooth refresh" off and now is up to 10%. Is a drawing a graph such a difficult task for performance monitor?

But this is nothing to compare to what happened next:
Processor went crazy up to 100%. in This same time processes looks normal. No matter witch machine.

I am loosing my faith in Linux when I see this kind of stuff.