Since the introduction execute-like mechanics such as hammer of wrath and molten fuy there has been a long-standing assumption that the optimal time to use bloodlust and other dps cooldowns is during the period at which dps is at its greatest; namely below 35% health. This article will show that this is incorrect and that, infact, there is no noticeable difference in the total fight length regardless of when bloodlust or trinkets are used. When there is a difference it may favour early or late cooldowns, depending on the circumstances.
The major consideration of this discussion is: When is the best time to use bloodlust? As bloodlust is the only raid-wide fixed duration dps cooldown, it enforces a raid-wide synchronization of dps cooldowns.
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The correct time to use dps cooldowns, when there are no other extraneous factors, is at that point when the raid can leverage the most fixed-duration cooldowns simultaneously. Execute is not such a cooldown as its duration is not fixed. This will normally mean using cooldowns early in a fight when it is easier to synchronise across the entire raid.
The exception to the above is when a boss fight is such that a specific phase needs to be completed in the shortest possible time (a la C'thun, M'uru/Entropius, RoS... etc.).
Early use of DPS cooldowns can cause problems for classes with aggro-reduction abilities on a long cooldown. One solution is to ensure at least one of your rogues/hunters keeps their aggro-redirection abilities for during the burn period when their damage, and hence transferred aggro, will be maximized. Alternately, save the cooldowns for 85-80%.
(1) Use cooldowns simultaneously.
(2) Obeying (1), use cooldowns early to maximize the number of people and cooldowns available,
(3) If one particular phase needs to be burnt through in the shortest possible time, use cooldowns during that phase, still obeying (1).
The Biggest winners/Losers are Warlocks and Hunters, even mages see a net change of less than 50dps between early and late BL. Note, warriors, paladins and deathknights are not included. This Simcraft calculation shows that there is only a 0.056% difference in average raid dps (and therefore fight duration) between using bloodlust early and using it late; this supports the hypothesis that there is negligible difference in the fight length when BL is used below 35%.
x: dps above 35%
y: dps below 35% (so y > x)
H: Boss health
A: Multiplicative modifier from popping cooldowns (example: Bloodlust/Heroism)
B: Additive modifier from popping cooldowns (example: Clickable trinket with +damage or AP)
T: Time to kill without cooldowns
T_1: Time to kill with early cooldowns
T_2: Time to kill with late cooldowns
I'm assuming that cooldowns will always work for the full duration, which I've set to 40 sec.
Using no cooldowns you get:
Assuming purely multiplicative cooldowns:
With a bit of elimination, it's clear that in this case .
Assuming both types of coolodowns:
Unless I messed up (not unlikely) this eliminates to: (i.e. it's better to pop cooldowns early).
[top]Proof that trinkets should be stacked with BL
Originally Posted by Ichal
As x > 0, A,B > 1 and H = H_1 + H_2. Which means T_2>T_1. (Why is the forum ending that with a '='?).
So again T_2 > T_1 for the same reasons.
Because the above is quite general, it applies to all cooldowns, and not just bloodlust/trinket. It is optimal to use all your cooldowns at the same time.
Though the results are counter-intuitive there is a (relatively) simple explanation for them. Unlike other dps enhancing effects, execute scales with the mobs HP, and so can be modelled as a flat reduction of the mobs HP; if below 35% every point of damage effectively becomes X points, then the monster's effective hp are scaled by 1/X. If we apply execute as a HP change, not a dps change, it becomes obvious that it does not matter when we BL.
This model makes a number of assumptions, the largest of which is that multiplicative effects (such and bloodlust) are symmetric above and blow 35%, when this does not hold then the their use will within execute range can change the total fight length. However, it does not mean that it is always the correct to use them during the last 35%:
Originally Posted by MatsT
Joe the Wizard output 100 dps. When the boss drops below 50%, his damage increases to 200 dps due to cool talents. Greg the Lizard Lord can also output 100 dps, but unfortunately he has no talents that increases his damage at low boss health. When Greg pops his bloodlust, Joe's dps is doubled. Greg does not benefit from bloodlust at all. In conclusion.
Joe: 100 dps without bloodlust, 200 dps with.
Greg: 100 dps without bloodlust, 100 dps with.
Joe: 200 dps without bloodlust, 400 dps with.
Greg: 100 dps without bloodlust, 100 dps with.
Now consider the two cases of popping bloodlust early and late in the fight. Let's set boss hp to 100k
40 seconds of 200+100dps, meaning 12k damage.
190 seconds of 100+100dps, meaning 38k damage.
167 seconds of 200+100dps, meaning 50k damage
Total: boss dies after 397 seconds.
250 seconds of 100+100dps, meaning 50k damage.
40 seconds of 400+100dps, meaning 20k damage.
100 seconds of 200+100 dps, meaning 30k damage.
Total: boss dies after 390 seconds.
Originally Posted by Wraithlin
To reverse your example
A = Above X%, Below X%, (with BL)
J = 100, 200 (100, 200)
G= 100, 100 (200, 200)
Joe has an execute talent but does not scale with haste. Greg scales with haste, but has no execute talent.
100k HP, BL early
40*(200+100) = 12k
167*(100+200) = 50K
Total time = 397
100k, BL late
250*(100+100) = 50k
40*(200+200) = 16k
113*(200+100) = 34k
Total = 403s
What matters is the total percentage change in raid dps when cooldowns are used. It is not always clear which part of the fight is optimum for cooldowns: some classes classes will scale better with haste below 35% than above it (eg mages, warriors, warlocks); some will scale worse below 35% than above it (eg hunters, paladins), and some will not change noticeably (eg rogues, druids, deathknights). Overall the differences are very small, and we can consider them insignificant for all real systems.
Originally Posted by Nevets_69
I did up an excel spreadsheet based on his scenarios to really take a closer look. Here's the summary:
Boss Health 600000
Early Bloodlust Late Bloodlust
Early Late Early DPS time Late DPS time Early DPS time Late DPS time
Scenar No BL w/ BL No BL w/ BL BL Time Non BL t BL Time Non BL t Total BL Time Non BL t BL Time Non BL t Total
1 2500 3000 2500 3000 40 72 0 120 232 0 120 40 72 232
2 2500 3250 3750 4875 40 68 0 80 188 0 120 40 28 188
3 2500 3010 2550 3075 40 71.84 0 117.6470588 229.4870588 0 120 40 69.41176471 229.4117647
4 2500 3100 3000 3750 40 70.4 0 100 210.4 0 120 40 50 210
5 2500 3240 3700 4800 40 68.16 0 81.08108108 189.2410811 0 120 40 29.18918919 189.1891892
There is a small advantage to splitting trinkets when the raid has no bloodlust at all. In this situation, those without an execute multiplier on damage should trinket early, and those with such a bonus should trinket late; again, the difference is marginal. This only applies to a fight length shorter than trinket CD, otherwise one could double trinket early and late.
Originally Posted by MatsT
Super trinket gives 100dps for 10s, Mage does 200sp, rogue does 100dps, MFury is +10% dps, 20k boss health.
Rogue trinket early, mage trinket late:
10s @ (100+100) + 200 = 400 = 4k total
51.67s @ 100 + 200 = 300 = 15.5k total
10s @ 100 + (200+100)*1.1 = 430 = 4.3k total
19.4 @ 100 + 200*1.1 = 320 = 6.2k total
Total time = 91.07s
Both trinket late
65s @ 100 + 200 = 300 = 19.5k total
10s @ (100+100) + (200+100)*1.1 = 530 = 5.3k total
16.25s @ 100 + 200*1.1 = 320 = 5.2k total
Total time = 91.25s
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Wonderful post, although there are a few things I would like to add.
I think that there are two diffrent kind of cooldowns: haste and damage cooldowns.The diffrence between them is that it is useful to stack haste + damage cooldowns at the same time, or damage + damage cooldowns. Although, stacking haste + haste is not worth it, according to my calculations/
Lets take for example a frost mage who is spamming frostbolt. Now assume that he is totally naked and is only wearing [Scale of Fates]. That means that his only haste abilities are Icy Veins and [Scale of Fates]:
Normal : 3 sec cast --> 13.33 casts in 40 seconds
Trinket : % spell haste = (432) / (32.79) = 13.2 New Casting Time = (3 sec) / (1 + ((13,2%)/(100))) = 2.65 sec cast --> (20 sec)/(2.65 sec) = 7.55 casts in 20 seconds
Icy Veins : New Casting Time = (3 sec) / (1 + ((20%)/(100))) = 2.5 sec cast --> (20 sec)/(2.5 sec) = 8 casts in 20 seconds
Trinket + Icy Veins : New Casting Time = (3 sec) / (1 + ((13,2% + 20%)/(100))) = 2.25 sec cast --> 8.88 casts in 20 seconds
In other a 40 sec test:
Normal (40 sec) = 13.33 casts
Trinket (20 sec) + Icy Veins (20 sec) = 7.55 casts + 8 casts = 15.55 casts
Icy Veins + Trinket (20 sec) + Normal (20 sec) 8.88 casts + ((13.33)/(2)) casts = 15.545 casts
Benefit: 0.05 seconds
NOTE: benefit will increase by amount of haste you already have (by gear or bufs) (personally I have a ~4% damage boost by not stacking trinket + Icy Veins)
Also, I think there is another reason why using bloodlust early is better than using bloostlust when a boss has lower than 35% health:
By using it early, it will decrease the amount of time that you can't use any execute effects. In other words: if you use it early, you can start earlier using execute effect against the boss. Which will result into a quicker death (I am sorry but I havent tested this yet, will come soon hopefully.)
You need to be careful when doing math for stacked Haste effects. Effects that increase HR are additive with each other. Most other affects (and I assume that Icy Veins is in that category) are multiplicative. Changing your
3/(1+.132+.2) = 2.25 sec cast
3/(1+.132)/(1+.2) = 2.21 sec cast
would reverse your conclusion.
Spellcasters whose rotation has an instant-cast (or a 1.5s cast) spell, have a soft haste cap at just 50% haste, which is very easy to reach, particularly with Bloodlust. Depending on your gear and complete rotation, you might have a reason to avoid stacking haste cooldowns.