I agree with Magic. Shot placement or even being able to get into position for the shot is more important, I believe. Speed is important to a certain degree, but my Vectrix at 63#only shoots my 501gr (heavy)arrow at 250fps (slow by todays standards), but I get 69 1/2 ft/lbs of KE. That's what does my killing. I shot at 3 deer, a 7pt, and 2 doe last year killing all 3 with pass throughs. One of them, a big doe was 30yrds out!I would have to see a deer jump my string at 20yrds or closer to believe it!
A deer that can do that was already on edge, caught odor and or movement.