I'm hoping for replies to the above, but in the meantime I've been running it a couple of days without the (slow WD "green") backup drives to see if that affected anything.
It doesn't seem to have made a difference, but I believe I might have pinpointed the reoccuring spinning beachballs to Firefox. I do have the latest version, which I've read should be very effective, so that puzzles me.
Recently all my open tabs were gone (they should be on my backup drives though, if I can only figure out how to get them back) which means I've been running it with just a single window and a few (perhaps 10) tabs open at once, but alas, still the spinning beachball.
If someone could please fill me in on how to determine the usage/load of each tab as I understood someone earlier in the thread did it could help me determine if certain sites cause more problems than others.
I need to look closer into this -probably refrain from using Firefox for a while and see if I get better performance with Safari.