The Task Manager is exactly where I was looking - under the performance tab. All 6 cores do appear (I have hyperthreading disabled as Steinberg has not declared official support for it that I am aware of. Please correct me if I am wrong here.). Each core appears to be doing a little bit of work, but only maybe 1 or 2 at most are really working hard. The others are doing very little. I think the reality is that Cubase just doesn’t really use all of them completely.
Maybe I should enable hyperthreading so I have 12. Would that make a huge difference? ALSO, my motherboard allows for a 2nd processor… maybe I should add another 6 core processor, so that with hyperthreading active, I would have 24 cores total. Would that make a difference? - or would Cubase still mainly use just one or two cores?