Controlled Destruction vs Iron Will

[mss73055]

I wonder how Iron Will is working. Or more: why it does such a poor job.
I made a 2L to check it out: Scorch + support gem.

Single Scorch does 2500

Controlled destruction (43%) adds ~1000. What is understandable.

Iron Will (37% and 400 strengh) adds 500. That's welllll .. silly.

Anyone got an idea why Iron Will is underperforming by a factor 3?

[Geronimo]

I'm going to take a shot in the dark here and say it might have to do with the way damage is calculated and added. For example Iron Will's % might be added at a smaller instance before end calculation thus gaining less damage boost. Whilst Controlled Destruction could be calculated more towards the end of the formula giving a greater boost due to the fact Iron Will converts then adds while Controlled just adds.

Edit: http://pathofexile.gamepedia.com/Game_mechanics#Damage_Scaling_and_Effects

[Gus the Crocodile]

Yeah, it's all about the difference between "increased" bonuses (these stack additively together) and "more" bonuses (these stack multiplicatively).

If you already have lots of "increased damage", then 43% increased damage isn't going to be taking you from 100% to 143%, it might be taking you from, say, 300% to 343%, which is a relatively smaller difference. But "more" damage is just multiplied, so if you had 43% more damage, it would take that 300% to 300x1.43 = 429%.

Keeping the difference between those two terms in mind will be very helpful in assessing what gems, items and passive skills are best for you.

[mss73055]

This may be very well the case.
My spell power modifier was 340 bonus + 100 base = 440 total.
400 strengh added to spellpower.

Some guesses
80 + 37 = 117 : 26%
80 * 1.37 = 109 : 25%
80 and "37%" not counted: 18%

The last guess is my best fit so far: Strengh bonus is added to the talent bonus. And the 37% modifier is not applied at all.

[Fatal Error]

Iron will is increased. Controlled destruction is multiplicative (more). I suggest you read the poe wiki. http://pathofexile.gamepedia.com

[OhhPaigey]

Controlled Destruction is OP.

Me and a friend were discussing just the other night as he was using the Iron Will gloves unique, and switched away from them right afterwards lol.