Flammability and Fire Penetration - is there a sense to use both?

Hey mates

As in topic - do these skills cooperate in total lowering fire resistance of an enemy?
Some elaborations please,ex:
1) enemy has 75% fire resist
2) enemy has 0% fire resist
3) enemy has 100% fire resist
assume 20lv of gems,no quality.

Yes, especially for burn builds. They do work together, although slightly differently. The curse takes effect first, then the game checks for resistance cap (always 75% for monsters), then penetration is applied for skills that hit (damage over time cannot penetrate).
This means vs enemies that have very high resistance (100+, this can only happen with map mods) your curse might be ineffective and you'll end up in the same place with penetration gem only.
Vs enemies that have very low resistance you might be better off with another dps curse, like Assassin's Mark (although resistances can do into negative providing a damage multiplier)- unless you're a burn build, in which case you want all the resistance reductions you can get.

penetration suppresses a part of the maximum resistance for your whole hit, curse reduce the actual resistance of the target.


Penetration has ONE advantage, it always work against OVERCAPPED resistance:
if the opponnent has 75 resistance max but 150% overcap resistance, a curse with -35% will be uneffective (150 -35 is still above 75).

However the penetration will remove 37% resistance for the whole hit, (so the opponent has 38 res left but with still 150% overcapped resistance behind!)
In this special case, the penetration has more than doubled your damage on the target.


And yes, both are cumulative if the opponent doesnt have overcapped resistances.

against a 0% res monster, 35% curse + 37% pene = 72% more damage for -72% negative res

Thank you very much guys.Especially you Vipermagi,as usual it can be counted on you.