Guys, Fedor has definitely slowed down...
But... Fedor has never been only about the speed, he has always been about the TIMING. He is able to throw those ridiculous overhands because he times them so well. He sizes opponents up, times them, and then commits EVERYTHING to one punch. Look at his recent fights: with Arlovski, he was struggling to time him at first, then as AA was about to jump into that flying knee Fedor is already throwing a punch. The same with Rogers: he misses one overhand right at first, but that's ok, he times the next one perfectly. As Rogers is about to throw his punch, Fedor commits everything and catches him on the button at exactly the right moment.
Fast fighters don't need perfect timing because they can overcome it with sheer speed. Fedor just anticipates where his opponent is going to be in 1-2 seconds - That's EXPERIENCE. You can be the slowest fighter in the world, if you can anticipate where your opponent will be in 5 seconds you can KO anybody.