User blog comment:StrategicMagic/Vayne - Carry? Yes. AD? No./@comment-4636093-20120819002253

You require 13 silver bolt procs to take down someone from full. With your base AD and the flat true damage from the 3rd strike added in it would be between 7 and 10.

At 2.5 attacks a second you take 1.2 seconds to land your third hit.

Basically it would take 8-12 seconds to kill a single target with your build.