Board Thread:League of Legends discussion/@comment-24603390-20140317093853

If the increased physical damage from the 35% amour penetration can be thought of as increased AD, the passive must increase damage by 23.89 points (860g/36g per AD = 23.89 AD), in order to be gold efficient. For this to occur, “Arm*(AD-44.367) > 6825.7”, where Arm is the targets armour. This can be rounded to “Arm*(AD-45) > 7000”, for ease of remembering. A graph of the unrounded equation can be seen below.



An example of this is a champion with Last Whisper and 110 AD auto-attacks an enemy champion with 100 armour, the Last Whisper is not efficient (100*(110-44.367) = 6563.3 < 6825.7).

However if another champion with Last Whisper and 120 AD auto-attacks the sam

e enemy champion, the Last Whisper is now efficient (100*(120-44.367) = 7563.3 > 6825.7)

The equation can also be applied to abilities that scale with 100% AD, such as Ashe’s Volley. If Ashe with Last Whisper and 130 AD auto-attacks an enemy champion with 50 armour, Last Whisper is not efficient (50*(130-44.367) = 4281.65 < 6825.7). However if she uses level 3 Volley with 60+130=190 damage, Last Whisper is efficient (50*(190-44.367) = 7281.65 > 6825.7).

These examples assume no other form of armour penetration/reduction and 0% crit chance. As a general rule, the higher your AD and the higher the targets armour the more efficient Last Whisper will be.  