If I can do 10 mph in the biggest ring up front at 90 cadence and 10 mph in the second ring at 90 cadence, which is better? Does it depend on what you are doing?

For efficiency, I can see the 2nd ring working, but you'd spend forever getting there. However; you'd get there faster with the larger ring, do more work, but would't that save lots of time in the end so you wouldn't need to be so efficient?

Or is it more of a short distance/long distance thing?