The secret to Floyd's jab is that he usually throws it from a hand position that the smart guys in here like to advocate - from the chest level or below. Not only does it come from a position that is a little outside of his opponent's field of vision but it is simply a more natural, fluid and therefore faster way to throw it. From here he can also choose to throw his best punch (and perhaps the most underrated, safe and consistently effective punch in boxing) - the jab to the solar plexus. The reason why Floyd is able to land the jab so effectively is not because of pure speed but because he is constantly feinting a number of different options. Once again you can't effectively feint if your gloves are glued to your ears because from there your opponent can always see both your hands. In my opinion this is why a lot of the undercards feature guys earmuffing toe to toe who are able to engage in constant and seemingly brutal exchanges. This isn't just because they take punches to the gloves but because even if they end up getting hit left, right and center they are able to track most of the punch trajectories because they are coming from an eye-level position. Now because Floyd's opponent becomes wary of everything the left hand is doing below he is able to sneak in lead rights from above and over the top. A lot of the time later in a fight Floyd will sucker guys by simply glancing at the belly before unleashing a right hand to the head then rolling under and away. He's also able to land his lead left hook because he'll lower his weight and trail his left hand as if to throw that jab to the solar plexus but when his opponent mirrors him but drops his right hand to parry he whips in the left hook to where their glove should have been.

If you want a mind opener search through Ask the Trainer threads featuring greynotsoold, Andre and Chris Nagel. They go into more detail about "old school" and "alternative" techniques and concepts that are really just the proper ways to box.