If you want to see some controlled testing of various tires at various pressures check out this site:
https://www.bicyclerollingresistance.com/
I was surprised to find that my nice, thin, slick Schwalbe Kojaks perform
much worse than heavier, bigger, rugged and treaded Schwalbe Almotions. It's remarkable what actual testing can reveal.
While tire pressure certainly makes a difference, the construction of the tire and compounds used seems to be the most significant factor.
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