SWTOR: Primary Stat or Power for more Damage/Healing?
When is Power better than a Primary Stat (Aim, Cunning, Strength, Willpower) in SWTOR?
is there a reason Arsenal Merc mods are focused on Power instead of Aim?
are you implying that the stat priority is different only for augment slots? Why is this?
Choosing between your Primary Stat and Power in Star Wars: The Old Republic can be a confusing affair as Primary Stats and Power interact with your character in different, but related ways. The choice between a Primary Stat and Power is most frequently encountered in Augments and a little bit of math can help us determine why Power Augments are often superior to Primary Stat Augments.
Update: October 7, 2012
Now includes math for talents and buffs that increase your Primary Stats and Damage/Healing.
Power vs Primary Stat
Power and Primary Stats both contribute to your character's overall damage or healing, but at different rates and in different ways.
Why do Primary Stats contribute less Damage or Healing than Power? That's because Primary Stats also contribute a small amount of Critical Chance. This bonus equates to ~.007 Crit per Primary Stat. At 1000 Primary Stat, you receive a bonus to your Critical Chance of ~7.13%.
All Primary Stat Augments come in the same variety with +18 Primary Stat and +12 Endurance. As an example, see the Advanced Reflex Augment 22. With this information, we can estimate the contribution that a Primary Stat Augment makes to your damage or healing.
18 Primary Stat * .20 = 3.6 Damage
18 Primary Stat * .14 = 2.52 Healing
18 Primary Stat * .0071 = .128 Crit
What about the +Primary Stat talents like Ironsights? These talents add up to 9% to your Primary Stat.
18 Primary Stat * 1.09 = 19.62 Primary Stat with +9% from talents
19.62 Primary Stat * .20 = 3.924 Damage
19.62 Primary Stat * .14 = 2.747 Healing
19.62 Primary Stat * .0071 = .139 Crit
What about +Primary Stat buffs like Mark of Power? These buffs add 5% to your Primary Stat.
19.62 Primary Stat * 1.05 = 20.601 Primary Stat with a +5% buff
20.601 Primary Stat * .20 = 4.120 Damage
20.601 Primary Stat * .14 = 2.884 Healing
20.601 Primary Stat * .0071 = .146 Crit
The most common Power based Augment, Advanced Overkill Augment, provides +18 Power and +12 Endurance.
18 Power * .23 = 4.14 Damage
18 Power * .17 = 3.06 Healing
What about +damage/healing buffs like Unnatural Might? These buffs add +5% to your Melee, Ranged, Force, and Tech damage/healing modifiers. They do not impact your Crit.
Primary Stat: 4.120 * 1.05 = 4.326 damage
Primary Stat: 2.884 * 1.05 = 3.028 healing
Power: 4.14 * 1.05 = 4.347 damage
Power: 3.06 * 1.05 = 3.213 healing
The small amount of Critical Chance provided by the Primary Stat Augment is not enough to offset the raw Damage / Healing bonus of a Power based Augment, especially at higher levels of Primary Stat where the bonus to Critical Chance begins to hit severe diminishing returns. Further, this is still true even when factoring in a possible +9% to your Primary Stat from talents and the +5% Primary Stat buff.
Why does Noxxic recommend Primary Stat > Power?
Our general recommendation of Primary Stat > Power comes down to a few considerations.
You are only forced to choose between Primary Stat and Power on Augments and some Mods.
Our Mod and Augment recommendations take the value of Primary Stat and Power into consideration and we recommend the items that provide the highest overall bonus to Damage or Healing.
Outside of these two conditions, Primary Stat provides more value than your other stats.
