Its a difficult topic..

There are a few things i ponder on when thinking of my answer and looking at others answers

One is things like how to define speed like a roy jones compared to a james toney and a Tapia

Toney and tapia are more likely to appear to be fast.. They both tend to flurry, Tapia would sometimes come forward with continuous straits.. and both flurry to the body and come up to the head..Its like three down stairs and come up with hooks and uppercuts..while roy was just crazy fast and snappy popping out fast punches one two three at a time with ease and the way in which he throws is different..#

Another matter i think of is this..

Rafael Marquez..Yes fast im sure.. But not of that style.. I suppose style aids speed..

If you were to put a R Marquez and An Andre Berto in front of me i bvelieve most would favour berto..

Its just the strange way in which the style of punching and pop favours the speed