I would be tempted to do away with your .kde directory, and log in again just in case you have some residual nonsense lying around from a previous version.
FYI, I am running the very latest KDE in current with desktop effects enabled, and various desktop widgets monitoring temp, mem, network, cpu usage, calender etc and only very rarely do I see cpu usage creep much above 20% across both cores, even with FF open with 8 tabs it doesn't get any higher than that.

1 members found this post helpful.

Thanks for the idea. That did it.
Guess I could have gone about it from the opposite direction, but I renamed the .kde file, rebooted and started fresh. It idled at 0-1% or 1-2% or 2-3%. I left Gkrellm up and running while I configured the desktop and when I let it "calm down" it would return to the 1-3% range.
Once the widgets and program icons were added to the desktop and panel, the CPU usage, when idling, didn't change. Then I remembered to add the keyboard LED widget for this wireless keyboard (won't buy another one when this thing dies) and the CPU usage jumped to as high as 27 to 30%. Removed it and CPU usage went back down. I did this 3 times with the same result each time. The culprit is named, "Netbook LEDs, version pre0.1."