Size, speed and strength, those are the most basic aspect of talent evaluation. Instincts are important, but good coaching can go a long way toward overcoming that aspect of player development is the three S's are there.
Having said that, here's some 40 times of interest from the Combine.
Okoye - 5.00
Branch - 5.01
Patrick Willis - 4.49
Lawrence Timmons - 4.59