Eclipse: Part1 - Which Buff is Best?

My long time readers know that I did a couple of posts back in October on the state of Eclipse. Those posts are now very out of date and it is long past time to present the new math to you guys.

This is part 1 in a four part series looking at the Balance Talent Eclipse. In this post I look at the two Eclipse buffs and show which is the better buff. Part two will look at the value of Eclipse and try and provide you with an idea of how it will help your DPS. Part 3 will try and answer the question, Should you reapply DoTs during Eclipse? Finally, Part four will summarize my findings and I will share my general thoughts about the talent.

For those of you that don't like reading math, please feel free to skip to the bottom for my TL:DR version of the post.

Which Eclipse is Better?

Eclipse: When you critically hit with Starfire, you have a (33%, 66%, 100%) chance of increasing damage done by Wrath by 20%. When you critically hit with Wrath, you have a (20%, 40%, 60%) chance of increasing your critical strike chance with Starfire by 30%. Effect lasts 15 sec and has a 30 sec cooldown.

So, obviously you can use Eclipse to buff Starfire or Wrath but not both within the same cooldown. So the question is: Which spell should I try to buff with Eclipse? To determine that we need to see how Eclipse both spells.

Assumptions:

1. I'm using fairly entry level DPS stats for a fully raid buffed Moonkin. They are 2000 Spell Power, 35% Crit chance (38% for SF), 17% haste, and 100% hit chance. On the armory this moonkin would probably have 1650 SP, 15% Crit chance, and 6% haste.

2. I assume a build very similar to this one. I realize that some of you will have more mana regen and will probably drop Imp IS or Imp FF to get there. Even if that is the case I don't think you will have a hard time getting to the 35% crit represented in the math.

3. I assume that Moonfire and Insect Swarm are always on the target and don't need to be reapplied. Therefore, my calculations take full advantage of Improved Insect Swarm.

4. My calcs assume that a [Chaotic Skyflare Diamond] is equipped.

5. When calculating the DPS numbers for Starfire and Wrath I am assume their respective idols are equipped. Please note that I am not suggesting you do any kind of idol swapping. Idol swapping is bad. I'm just doing this to balance the numbers and be fair.

Wrath:

The average DPS for a normal Wrath Cast looks like this:

Avg Non-Crit Wrath = ((((658 + (2000 * 0.6714))) * 1.13) * 1.0712) = 2421.88
Avg Wrath Crit = (((((658 + (2000 * 0.6714))) * 1.13) * 1.0712) * 2.09) = 5061.73
Avg Wrath Cast Time = (((1.5/1.17) * (1 - 0.35)) + 0.35) = 1.1833

Therefore,

Avg Normal Wrath DPS = ((2421.88 * (1 - 0.35)) + (5061.73 * 0.35)) / 1.1833 = 2827.54 DPS

The average DPS for a Wrath Cast with Eclipse looks like this:

Avg Non-Crit Eclipsed Wrath = ((((658 + (2000 * 0.6714))) * 1.33) * 1.0712) = 2850.53
Avg Eclipsed Wrath Crit = (((((658 + (2000 * 0.6714))) * 1.33) * 1.0712) * 2.09) = 5957.61
Avg Wrath Cast Time = (((1.5/1.17) * (1 - 0.35)) + 0.35) = 1.1833

Therefore,

Avg Eclipsed Wrath DPS = ((2850.53 * (1 - 0.35)) + ( 5957.61* 0.35)) / 1.1833 = 3327.99 DPS

So, as you can see Eclipse will increase Wrath's DPS by 17.70% ( (3327.99 - 2827.54 ) / 2827.54).

Starfire:

The average DPS for a normal Starfire cast looks like this:

Avg Non-Crit SF = (((1285 + (2000 * 1.20))) * 1.1) * 1.0712 = 4342.11
Avg SF Crit = ((((1285 + (2000 * 1.20))) * 1.1) * 1.0712 ) * 2.09) = 9075.01
Avg SF Cast Time = (3 - (0.5 * 0.38)) / 1.17 = 2.4017

Therefore,

Avg Normal SF DPS = ((4342.11* (1 - 0.38)) + (9075.01* 0.38)) / 2.4017 = 2556.78 DPS

The average DPS for a Starfire Cast with Eclipse looks like this:

Avg Non-Crit SF = (((1285 + (2000 * 1.20))) * 1.1) * 1.0712 = 4342.11
Avg SF Crit = ((((1285 + (2000 * 1.20))) * 1.1) * 1.0712 ) * 2.09) = 9075.01
Avg SF Cast Time = (3 - (0.5 * 0.68)) / 1.17 = 2.2735

Therefore,

Avg Eclipse SF DPS = ((4342.11* (1 - 0.68)) + (9075.01* 0.68)) / 2.2735 = 3325.48 DPS

So, as you can see Eclipse will increase Starfire's DPS by 30.07% ( (3325.48 - 2556.78) / 2556.78).

How they Compare:

As you can see Starfire gets a much larger buff from Eclipse then Wrath does. In fact, Starfire with the eclipse buff does more DPS on average then Wrath does with the eclipse, but they are very close. I have run these numbers at several gear levels. The margin between Starfire and Wrath will decrease as Crit increases but it's not much and Starfire still beats Wrath in total DPS if there is a comparable increase in Haste.

On top of that it goes with out saying that Starfire with eclipse is more mana efficient and will benefit more from raid buffs like Heroism then wrath will with the eclipse buff. I think we can conclusively say that the Starfire Eclipse buff is the superior buff.

TL:DR Version

In terms of damage out put the two Eclipse buffs are very close with Starfire buff doing a little more DPS per spell cast. From a DPM perspective the Starfire buff is the clear winner since Starfire is the more mana efficient nuke and the buff just makes it more mana efficient.

In my opinion the Starfire Eclipse buff is clearly the superior buff. (i.e. Wrath until Eclipse and then Starfire)

Edit: There is one exception to this that I know of. My math assumes normal levels of crit. In fights that buff your Crit Chance like Loatheb, the Wrath Eclipse buff becomes better. (Thanks to Beefkin for reminding me of this.)