(racer) Standard vs compact crankset: Increased leverage for same gear ratios true?
While it's true that a larger chainring will have slightly less friction and thus slightly more efficiently, it's an extremely negligible amount, that you wouldn't be able to feel. More importantly, are your crankarm lengths different on the new crankset than the old? That makes a much bigger difference. For example, if you've went from 175's to 170's, that will be a noticeable difference that could more likely explain what you're feeling.