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### [Math Thread] Armor Penetration vs Attack Damage Runes

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renticletape

Senior Member

Which is better? They both give you the same thing - more damage. However, I think the attack damage runes are obsolete in comparison to the armor pen runes. Armor pen scales your bonus damage based upon how much damage you currently have, and inversely by how much armor your target has.

The damage reduction for armor is as following: DMG - DMG*ARMOR/(100 + ARMOR)
Stacking all armor pen runes gives you about 46 armor pen.
Stacking all attack dmg runes (per level) gives you about +38 dmg at lvl 18 or + 2.13 dmg at lvl 1.

I will give a few examples at lvl 1:
Say your base damage is 50, and your opponents armor is 25. With the bonus attack damage, you get about 52 dmg lvl 1. After armor reduction, you will inflict about 42 damage.

Now lets say we got the armor pen runes. After calculating the -armor, you should inflict about 50 (because they have 0 armor) damage to your opponent. That's a difference of 8 bonus damage you dealt at lvl 1 with armor pen runes instead of attack damage.

Lets say your base damage is 120. and your opponent has 80 armor.
With attack damage runes, your damage is a total of 158.
The amount of damage you will inflict onto your opponent is about 87 dmg.

Now with the same armor pen rune page, and 120 base damage you will deal 89 dmg. Not much different than the attack damage runes, but still more.

These are just a few examples, but I have yet to find a case where the + dmg runes are more efficient. But basically armor pen gives you more damage than attack damage runes. Much more at lvl 1, and still more at lvl 18. Even worse, the more base damage you have, the more effective the armor pen runes are while the attack damage runes don't scale at all.

After some algebra, I have determined that the bonus damage from armor pen = DMG*ARMORPEN/(ARMOR - ARMORPEN + 100) assuming ARMOR - ARMORPEN >= 0.

tl;dr: Attack damage runes are useless compared to armor pen.

Discuss.

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Vindico Atrum

Member

Brutalizers win games. True story.

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DarkeTiger

Senior Member

Armor pen doesn't send armor into negative values.

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Guinsoo

Recruiter

One way they are different is that penetration cannot go below 0.

This comes into play with minions, who have 0 armor. So +damage is better against minions.

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Pharmacologist

Senior Member

Yes but since all champions have a default positive armor value as they level, armor penetration is absolutely, 100% unquestionably better than attack damage runes.

The OP is correct. Attack damage runes are horrible.

If you haven't noticed, runes are not remotely balanced right now.

Yes, damage works on minions, but getting 2 damage to last hit minions with is probably the weakest possible thing you can do with your runes.

While Guinsoo is here, please do something about crit damage runes : /

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BelialX

Senior Member

Yeah, but... they're minions. You can kill them easily regardless >.>

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MammothWaffle

Crit Damage wins all! Case closed.

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Toorc

Senior Member

I heart Desolation

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Pharmacologist

Senior Member

Desolation and crit dmg are pretty much king right now. Although crit % can occasionally give you a bs cheap first blood often, it just isn't as powerful overall.

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renticletape

Senior Member

Quote:
MammothWaffle:
Crit Damage wins all! Case closed.

True, but damage runes and armor pen runes also gives your more crit damage. The average DPS dealt total isn't much different.