okay!
Progress...time will tell if it completely solves the problem. Short version: disable KNemo in KDE Settings/Service Manager.
Extended version:
disabling kded totally is not a good idea. Look at KDE Settings/Service Manager. Several things depend on kded.
However...
I noticed that the cpu problem shows up when I plug in my wireless card. That activates KNemo-KDE Network Monitor icon in the panel.
The Nemo page
http://www.kde-apps.org/content/show.php?content=12956 explains the application. Indicates that this app is associated with KDE 3.5; I didn't have a problem before upgrading from 3.4 to 3.5.
One of the comments on that page refers to cpu usage and refers/links to a known bug. The bug report references ifconfig-checking each second.
Disabled KNemo in the KDE Settings/Service Manager. The problem disappeared along with the KNemo icon.