Hmmm.
MacPro has completed restored based on a Time Machine backup two days before I installed TeamViewer and the problem remains.
CPU still running at kernel_task over 1000% and very slow.
So, I need to change the title of this thread and edit it since it looks like TeamView is not the problem.
Now, I have shut down the can and have disconnected the power cable and will wait a minute and restart, to
reset the SMC.
Let's see if that works!