Ah, that it explains it!

I have (only) 4 GB RAM and seldom have more than a few pages open at the same time. Also, I quit Safari at least once daily.

If I understand correctly, even when new a new SL PithHelmet gets released, I will see no difference/improvement.

Thanks for your help/explanation Tacit.

Harv
27" i7 iMac (10.13.6), iPhone Xs Max (12.1)

Those who can make you believe absurdities can make you commit atrocities. ~Voltaire