Clearly since you were gimping your dps and that tank was still having problems holding your thread he is wrong. Vig is an amazing talent and i always use it when it raids. In heroics however im extremely lazy and since nobody really pulls off me anyways i often forget about it. If a dps asks or pulls threat then i will toss it on him and i would never tell somebody no. Bad pug tanks are bad and ones like him will never learn. The only time i ever put it on another tank is for festergut? i always always confuse the two when im tanking the slimes just so i always have a taunt available if needed.
If the 3% was additive maybe that would be true, but I'm fairly certain that is inacurate. ~4k armor I think is ~3% reduction (but it depends on your DRs). But that's a flat reduction.
Looking further (note smaller number here = better since it's in the denominator):
(1-.7)*(1-.03) = .291
(1-.73) = .27
So actually 3% more reduction to armor is better than 3% more reduction from vigilance buffs and the like. Remember, vig does not stack with BoSanc or Renewed Hope.
Doing some more napkin math:
.27 = .3*(1-x)
.9 = (1-x)
-.1 = -x
.1 = x
Therefore to equal a 3% increase in armor, an additional buff that is multiplicative (like all damage reduction effects are) would need to be about a 10% reduction, assuming no other effects.
It's still an effin' awesome talent though.
Edit: I probably should clarify. I don't expect to see another 9k armor on my toon. I'm just mentioning that for that amount I'll get less than 3% reduction from armor.
Is armor applied before other reduction effects? I don't see why it would be, but mechanics are mechanics and I've never bothered testing it. Maybe I should.
Last edited by Petninja; 06-03-2010 at 06:39 PM.
So is Vig worth putting on tanks as long as it doesn't gimp their threat or what because of the 3% dmg reduction?
A little more napkin math to show you how much armor vigilance is worth.
At 65% reduction from armor:
(1-.65)(1-.03) = .3395
(1-.3395) = .6605 reduction from armor needed.
.6605 armor reduction = 32363 armor
.65 armor reduction = 30893 armor
therefore if you have 65% armor reduction, or around 30893 armor, then vigilance represents the equivalent of a 1470 armor increase.
If you have 70% armor reduction (38815 armor) then you'd need an equivalent of 70.9% reduction in armor which is 40523, so vigilance is worth an equivalent of 1708 armor.
So actually since vigilance is a constant, it's actually worth more armor the more you have (since armor has DRs) but it actually is a smaller reduction in damage done (.9% vs 1.05%).
So yes, it's good, and if there is no negative to putting it on another tank and you don't have the 3% reduction from somewhere else, yes, it is absolutely beneficial to put it on another tank.
Edit: all damage reduction effects are multiplied at the same time, it really doesn't matter which comes first.
Say you just start with the 3% reduction from vigilance. Say the incoming it would be 100k raw damage. Now you're only taking 97k raw damage. Now add in the 70% reduction from armor(97k*.3), and you're now taking 29.1k damage.
Now say you start with the 70% reduction from armor, same incoming damage, you take 30k damage. Now add in the 3% from vigilance and you get 30k*.97 so 29.1k damage.
It's all multiplicative, so it doesn't matter which one comes first. The associative property of mathematics holds true again!