Hello Limnos, You get a 10!
I only found your first website reference useful. At first clearing the cache provided only a short lived temporary increase in speed. When I looked again at the %CPU usage in the Activity Minitor, Adobe Flash Player was hovering around 90% even when all websites were closed and nothing was going on. I uninstalled it and the Mac speeded up and remained fast, but needing the Flash Player, I was forced to reinstall it anew. The computer remained fast so obviously the former Flash Player was somehow contaminated.
Thank U again.