Talk:Nasus/@comment-24663301-20140630003448/@comment-9008617-20140723154758

"Take idoneous 54.1 armor vayne at lvl 12. 19 Armor penetration increases your damage by 14% on her. Higher armor targets will make armpen less effective. At 100 Armor you get a 10% increase in damage. 6% at 200. With AD runes you get extra damage on every auto attack. Armor pen is good stacking it with last whisper, but nasus can't allow that on his kit.

We can also factor in nasus E to make armpen more worth, in this case you add a 20 armor reduction (lvl1 E)  on 54.1 Armor (34.1 with debuff) vayne your damage is increased by 16.5%."

Um..

No arpen (i.e. 15 AD runes

1 - 100/(100 + 54.1) x 100% = 35.1% dmg reduction

1 - 100/(100 + 54.1 - 19) x 100% = 26% dmg reduction

35.1% - 26% = ~9% difference

I'm not sure how you're crunching your numbers but they don't seem right.

In any case, the age-old problem of AD vs Arpen is the same. Arpen scales with AD whereas AD does not..

So what you're saying about AD always giving more benefit is not true. Arpen is also applied every AA - not just AD.

The theory stands that Arpen would be better for Nasus simply because his Q can scale indefinitely whereas flat AD runes will only mean +15 AD from the start of the game until the end of time.