It's improbable that anyone would deny that Khan is one of the fastest fighters in history but could he actually be Number 1 in the speed department at 135 or above, the all time fastest (ATF)?
Even Manny Pacquiao, who himself is considered an incredibly fast fighter, at one point needed to spar Khan in order to increase his overall speed, under specific instruction of Freddie Roach.
What this means of course is that when Khan was training at Wildcard, it was he who was considered the fastest fighter in the gym, surpassing Pacquiao's own speed significantly and setting a new benchmark for high octane punching.
So the question now remains, is Khan the ATF at 135+. the all time fastest puncher?
As usual you have Khan vastly overrated. He has fast hands but no faster than lots of other boxers and not as fast as many others. If his hands were as fast as you say they are he wouldn't have lost to Peterson who's hands looked just as fast. Russell Jr. is faster, Rigo is faster, Loma is faster, Pacquiao is faster, Canelo and Lara and Cotto are as fast or faster, Mattysse is faster, Mayweather and Spence are faster and many others have hands as fast or faster than Khan. There is no way to prove this one way or the other because hand speed can only be guessed at and not accurately measured. You always have Khan the best at everything in boxing. There are really two Khans. The real Khan who has 3 defeats he won't try to avenge and fights a softie once every 9 months and Super Khan who exists only in your wild imagination.
At 135 and over? Idk if he was faster than Camacho, Taylor, Pacman or Mayweather etc. I mean Khan's hands are very dam fast but at the very least you gotta pick Camacho over him, that dude's hands were bananas.
The fastest from Pakistan, only.
His speed is almost certainly unparalleled by a variety of different nationalities, maybe even unmatched by all nationalities collectively. But it's not a geographical or nationalistically-inclined question from the get go.