Talk:Armor penetration/@comment-189.6.192.110-20110802215658/@comment-4462863-20110921034836

That is a horrible build. Here is the proof...

Your build: 45 Armor Reduc, 95 Armor Penetration = 140 Armor off Enemy (Assuming they don't go under 0 because your Armor penetration wont go below 0, and since Reduction is calculated before penetration and we are talking about Tanks it is safe to assume that they wont go below 0) At this point ANY Champ with less than 140 will NOT be affected by the extra Armor Penetration.

With your build you have a 5 sec damage output of 593.11 (Source: LeagueCraft.com) and with a tank build of Amumu and 162 armor. Your armor Pen will bring his armor down to 22. Or a damage reduction of

100/122 = 0.8198 (This number represents the % of damage taken)

0.8198*593.11=486.155 (Actual damage output in 5 seconds)

With your current build you have no way to have a damage output of higher than 593.11, Which would happen if the enemy champ had less than 140 armor.

Now lets see what happens when we switch your Brut, for a damage item like B.F. Sword.

Your new stats will be:

5 sec Damage Output: 2327 (A lot higher than before) Armor Pen: 125 (Still a lot)

Same Scenario:

100/137 = 0.73 (This number represents the % of damage being taken)

0.73 * 2327 = 1698.54 (This is your expected damage output over 5 seconds)

When you stack armor pen items they start to lose their effectiveness. Just as attack speed, and attack damage will lose their effectiveness when they are over stacked.