I was mainly thinking about how fast pages/sheets load, e.g., my perceived speed is more a function of the host's server rather than my ISP/broadband DL speed. If that is correct, what is the nominal-optimal broadband speed?
Your d/l speed is a function of both the host's server's d/l speed
and your own broadband speed. (And as for page loading time, I think that's a function of the above, plus your Mac's capabilities, browser version included.)
By way of example, my max d/l speed is 785Kbps, and I get all of it on an Apple d/l, but I occasionally get as little as 40Kbps from others, my 785 notwithstanding.
I think the answer to your question
may be that "
optimal" is whatever speed/cost ratio makes you happy.
Sorry I can't be more helpful, Harv.