Hopkins moved more, punched more, and clinched less last night.
Do the math - that means he WORKED more last night and for 12 rounds.

Against Calzaghe he punched less, moved less, clinched more,
and took breaks on low blows.. but was winded after the 7th round.

The OP is 100% correct in saying that hopkins was a different fighter last night.
His cardio was much better and he was 10x more active and worked 10x harder then
he did against cazlaghe. Calzaghe did nothing to wear him down or tire him out, but
he got tired... Last night he didn't.

I'll argue that he was better trained for the fight tonight than against Calzaghe.