In message <jj9uvv4dccmmt5rmiii4ec9o9c6ooksu4m@4ax.com>, Jim K

There's probably another process poisoning your processor cache.  Have
a look at all processes running, the stuff in your systray, and
anything else like services to see if something is consuming
unexpected amount of resources.  Also, have you updated your AV
software to a new version?  It's possible that the AV is inspecting
the .sah files at each write.  That's a killer too.  You might want to
try excluding *.sah from your AV scanning.

Thanks for that.  I don't think that is the problem, but I've taken precautions.

This happened  sometime on Jan1 or two, when I went from one unit per six hours to one unit in maybe 19 or 20 hours.  But this was part of the holiday, a quiet time, and the machine wasn't being used much and certainly wasn't being required to run new software.  Checking continues...