Originally Posted by PineappleThis
Is there a difference between magic penetration and a reduction in magic resistance? I generally take them to be the same thing or achieve the same effect but just curious cause of the difference in wording. Would having 15% magic penetration be essentially bypassing 15% of the enemy's magic resistance?
If both were equal values, you'd be correct. However, this is rarely the case.
In the case of Sorc Boots they give a solid 15 magic penetration. That isn't 15%, that's just a straight 15 off of whatever their MR is. Versus something like Void Staff which is 40% magic penetration.
As far as the order in which it is applied (if you had Sorc Boots and
Void Staff) I'm still looking for that information.
EDIT: Thanks to TiberiusAudley
The order is:
% Based Armor Penetration
Flat/Linear Armor Penetration
I would only assume that anti-MR works in the same way.
Magic Reduction (Abyssal Scepter, Amumu's Passive)
% Based MR Pen (Void Staff)
Flat/Linear MR Pen (Sorc Boots)