I don't know you obviously so I don't want to assume, but this statement reveals a lack of knowledge about the sport.
Floyd did more than just buckle he had spaghetti legs after the buckle don't show biased gifs show the whole damn thing
And I thought you are knowledgable in boxing? You have to take everything relative to their status when the fight was fought. For Pac-Marquez fight, the fight was at superfeatherweight. Obviously, their bodies are at superfeatherweight condition (size, punch resistance, etc) and not meant to take a punch of a welterweight. The FMJ-Mosley was at welterwight where their bodies are acclimatized to that weight. Obviously, MOsley is harder puncher simply because he is a welterwight. But taken on a pound for pound comparison, they are probably the same. Their KO ratios are not very apart (JMM = 74%, Mosley 60%). Do you mean to say that Chop chop Corley punches harder than Mosley?
Shane Mosley's KO percentage is 84% Juan Manuel Marquez's KO percentage is 74% Shane Mosley is and always has been a FAR more threatening power puncher than JMM.
I thought Floyd was hurt more, evident in how the rest of the round played out. Pac I think pretty much retaliated straight away after that. Also if this is some sort of measure to compare their chins, Pac was caught mid-air with a great counterpunch combination, Floyd was hit with 1 flush shot. I think Pac's chin is much more tested, if not for the sole reason that he sticks it out there often enough to be tested.
My mistake, I had Mayweather's KO output. Anyway, pund for pound, Mosley might be the harder puncher but even JMM was bailed out with his power. It is not exactly a welterweight power but it is enough in the divisions he is fighting.