How Warlock DoTs Work in Cataclysm

Look out, Cynwise! The Training Dummy is sneaking up on you!

As part of the massive mechanics revamp that came in patch 4.0.1, substantial changes have been made to the way damage over time spells are handled in Warcraft.  The way you thought about DoTs in Wrath is now wrong; it’s time to start thinking of them the Cataclysm way.

Let’s take a look at the bread and butter DoT of Affliction: Corruption.

Setting aside abilities that refresh DoTs for a moment, in Wrath, the right way to refresh a DoT was to let it tick the last tick, then immediately refresh it, like so.

This gave you 12 ticks for 2 GCDs of work.  Warlocks need to evaluate the DPCT (Damage Per Cast Time) of a spell, and in this case we see that those 2 GCDs gives us the full value of each Corruption spell (6 ticks) in the most amount of time.

What you wanted to avoid, at all costs, was clipping the DoT.  Clipping your DoTs meant refreshing it before the last tick, like so:

Clipping the DoT overwrites the first cast entirely, so the final tick of the first one is cancelled out by the delay preceeding the first tick.  In the time it took you to cast two Corruption spells, you got 11 ticks instead of 12.  The DPCT of each Corruption has been lowered by 8% just because the DoT was clipped. That’s a huge DPS loss.

I like to think of it as a single unit, the pause first and then the tick.  Casting the DoT starts with the pause, ignoring the previous spell.

This has been changed for the better in Cataclysm.

If you cast in between the penultimate and final ticks, your first Corruption spell gets its last tick in, and then the duration is extended beyond that as you’d expect.  You don’t want to let it fall off, because then you’re introducing the lag we used to have, and you have about a 2 second window between ticks to refresh Corruption.

Why after the penultimate tick?  Why not refresh it all the time?

Well, let’s see what happens then.

This example shows refreshing the DoT after the third tick.  The fourth tick still happens – it doesn’t get clipped – but the duration doesn’t stack up to a full 36 seconds.  You get 10 ticks for 2 GCDs of work, or a 17% DPCT loss for doing this early.

Now, this doesn’t mean you should NEVER do this. In a real fight, your instant casts should be refreshed whenever you’re moving, especially now that they don’t clip a tick in the middle of the rotation.  If you’re moving, you should be casting your Curse, Bane, Corruption, and then Life Tap to keep up your mana. Never stop casting!

But standing still, yeah.  Wait until the second to last tick, then refresh the DoT.

THE ONE DOT YOU STILL DON’T CLIP

The new refresh mechanics are fantastic, but there’s still one DoT you let fall off.  Can you guess what it is?

That’s right: Bane of Agony.  Take a look at its ticks:

Bane of Agony hits REALLY HARD at the end. (Not quite to scale.)

Bane of Agony has quick (2 second) ticks that ramp up over the course of the DoT: 4 weak, 4 middle, 4 strong.  This makes it ideal for use while pet tanking, as the aggro starts off very slow and ramps up with the damage.

But it also means that if you refresh the DoT before the final tick, you’ll overwrite a strong tick with a weak one.

This is somewhat counterintuitive, given how Corruption works above.  You’d think that you’d get your strong tick off, and then 4 weak ticks.  But no, you get 5 weak ticks.  Strip off your gear and hit a training dummy, you’ll see it in the logs.  Everything goes smoothly, you get 24 ticks total, but during the refresh you’ll get 5 weak ticks.

So. Let your Bane of Agony fall off, and refresh it once it does.  Everything else? Hit before the last tick.

THE EFFECTS OF HASTE & HASTE PLATEAUS

Haste has changed so that it tries to fit more ticks in to a static spell duration, instead of reducing the duration with the same number of ticks.  Each cast can give you more ticks of a spell than before.  In Wrath, Haste could make an 18 second/6 tick Corruption spell a 13.5 second/6 tick spell, giving you a DPS increase without actually changing the DPCT of the DoT.

In Cataclysm, Haste adds more ticks into the existing duration, which maintains the same DPS, but increases the DPCT of each DoT.  Let’s look at the two models.

Haste reduces the amount of time between ticks equally in both models, so the ticks are coming at the same frequency.  Assuming spell damage has not been altered, then the DPS is exactly the same between each model.

What’s different is the DPCT of the DoT goes up dramatically in the Cataclysm model.  Over a boss fight, you will spend less time refreshing the DoT if it adds ticks within the existing duration instead of shortening the duration.  In a 5 minute fight, you’d spend 23 GCDs casting Corruption in Wrath, but only 17 GCDs in Cataclysm, for the exact same DPS.  That’s a 35% increase in DPCT.

This means you have gained 6 GCDs to cast other spells during that fight, just by changing the way Haste is calculated.  That’s pretty cool!

However, this new mechanic has created some interesting problems when stacking Haste.

See, the game now has to decide when it’s going to add another tick.  There’s a specific amount of Haste which will give you a new tick, and when you hit that level of Haste, your DPS goes up by a large amount. But Haste only really benefits your DoTs when it gets you over the threshold. This rounding off leads to a phenomenon called the Haste Plateau.

Here’s the difference between 24% Haste and 25% Haste:

A very small amount of Haste in the first scenario would add a big DPS boost.  Haste in the second situation doesn’t help very much (until you get near adding a 9th tick, of course.)

This is different from the Wrath method of simply compressing the DoT down – Haste scaled linearly with that model, with the more Haste added, the faster each DoT burned.  In the Cataclysm model, Haste scales in a quantum fashion – you hit a threshold where the game rounds off, you get another tick.  Then you plateau out until you reach the next threshold.

Here’s a graph, definitely not to scale, about how the different models worked.

This graph shouldn’t be taken as a DPS comparison between the two systems – it’s just a way to show the different kinds of scaling going on here.  (Besides, DPS should be static between the two models.)  But the idea is straightforward: there are Haste values where your DoT DPCT will take a big jump.

Now, you’re probably asking, what are those Haste values?  When do I need to start looking to prioritize Haste over Mastery or Spellpower?

Well, for a Destruction Warlock using Immolate in a raid environment, Elitist Jerks has the Haste Plateau values as: 157, 781, 1406, 2030.  My own testing shows that I don’t gain an extra Immolate tick until around 10% Haste, which I think was around 500 Haste.  Not having raid buffs is probably the reason for the discrepancy in our two tests, so I’ll just put both out there and encourage you to hit the dummies with your own gear.  Swap pieces in and out, reforge them, and then count the ticks on the dummy.

The most important thing to take away from this is that while Haste is, in general, very good for Warlocks (and other DoT-based caster classes), there are times that Haste will be better for you than others.  Also, different spells will scale differently with different amounts of Haste due to duration and intervals between ticks.  Bane of Doom (4 ticks every 60 seconds) scales poorly, while Bane of Agony (12 ticks every 24 seconds) scales really, really well.  Immolate, Unstable Affliction (5 ticks over 15 seconds) and Corruption (6 ticks every 18 seconds) are all on the same 3-second scale.

There's a lot of math in this part, so Cynwise is going to reenact some of her favorite parts of The Return of the Jedi for you. You're welcome.

AUTOMATIC REFRESHES AND HASTE

All of the above is important theory for warlocks to know, but in practice, Affliction Warlocks never worry about refreshing Corruption manually.  They keep it going with the Everlasting Affliction talent, which gives Haunt, Drain Life, and Drain Soul the ability to refresh it for them.  This DoT-refreshing ability simplifies the Affliction priority list considerably, because all you have to worry about is keeping Haunt on the target, as it will take care of Corruption.

But, Affliction still needs to keep Unstable Affliction and Bane of Agony rolling on a target, and those now have two different methods they’ll need to consider.

Demonology has joined Affliction in the DoT-refreshing camp, as the new talent Cremation refreshes Immolate when Hand of Gul’dan is cast.  This is cool, and helps reduce the complexity in an already complicated priority list.  But the Cataclysm Haste model can do wonky things to this refresh.

Take a look at the 24% Haste example up above.  See the dangling blue line at the end of it?  That’s a good conceptual representation of what’s going on – you’ve got almost, but not quite, enough Haste to make it to that last tick.  And the duration between the ticks is still really close.

But the DoT ends on the last tick.  So while it’s convenient to say that Haste doesn’t reduce the duration of DoTs in the Cataclysm model, it’s not entirely accurate.  But only Demonology warlocks refreshing Immolate with Hand of Gul’dan actually do need to worry about it right now.  Pay attention, Demo locks!

I mentioned earlier that the game has a way to determine when you get another tick on your DoT.  It takes the time between ticks – reduced by Haste – and divides the total duration of the DoT by that number.  It then rounds off the result to figure out how many ticks you’ll have.

In other words:

• Take the time between each tick – for Immolate, it’s 3 seconds.
• Apply Haste to it by dividing it by 1 + the Haste percentage.  For 9% Haste, it would be (3/1.09).  10% Haste would be (3/1.1).
• Divide the total duration of the DoT by the hasted tick speed to find out how many ticks the DoT will have.  Immolate is 15 seconds, so 10% Haste would be 15/(3/1.1) = 5.5 ticks.  9% Haste is 15/(3/1.09) = 5.45 ticks.
• Round that number to the nearest integer, so 10% rounds to 6 ticks, while 9% rounds to 5.

So while you get 5 ticks at 9% Haste, and 6 ticks at 10% Haste, keep one important fact in mind: the tick speed is not rounded off.  The spell ends when the last tick ticks.

DoT duration equals tick speed times number of ticks.  So the following Haste values give you the following values:

• At 9% Haste, each Immolate tick will take 2.7523 seconds.  You’ll get 5 ticks, for a duration of 13.76 seconds.
• At 10% Haste, each tick is 2.7273 seconds long.  You get 6 ticks, for a duration of 16.3636 seconds.
• At 15% Haste, ticks are 2.6087 seconds, you get 6 of them, and Immo lasts 15.65 seconds.
• At 20% Haste, ticks are 2.5 seconds long, you get 6 of them, and Immo is exactly 15 seconds long again.
• At 29% Haste, ticks are 2.32 seconds each, you have 6 of them, and Immo is 13.95 seconds long.
• At 30% Haste, ticks are 2.3077 seconds long.  This is the breakpoint for 7 ticks on Immo, and the DoT is 16.15 seconds long.

While this has interesting implications for Destruction (who should strive for 10% Haste no matter what), it is even more interesting implications for Demo.

Consider: Hand of Gul’dan is on a 12 second cooldown, with a 2 second cast time, before Haste.  That’s 14 seconds between each refresh of a spell that, unhasted, has a 15 second duration.  Okay, no problem, right?

Only, Haste can both shorten or lengthen the duration of Immolate, depending on the specific value.  It never goes outside a certain range (13.64-16.36 seconds), but the lower end of that range drops below the CD and hasted cast time of Hand of Gul’dan.

Take 9% Haste again.  9% Haste brings HoG’s cast time down to (2/1.09) = 1.8349.  With a 12 second CD, that means HoG can be cast once every 13.8349 seconds.  Awesome!

Except you’re refreshing a spell that has a Hasted duration of 13.76 seconds.  Oops.

There isn’t really a great solution for this, aside from Demonology locks knowing where their Haste is and making sure that they can effectively refresh Immolate.  The area between 7-9.5% Haste seems to be the really dangerous area; the next such place where this happens is around 29% haste, and the HoG cast time is only 1.55 seconds then.  So it’s not a big deal then, just at low Haste levels.

I don’t think the Cataclysm Haste mechanic is broken because of this issue.  I think, if any technical solution is really needed, dropping the CD of HoG to 10 seconds through a Glyph would suffice.

This is just one of those places where the math gets really interesting, and where a little bit of Haste stacking can go a long way towards improving your DPS.

Did you have any idea DoTs could be so fascinating?

A FINAL WORD FOR HUNTERS (AND ROGUES AND FERAL DRUIDS AND…)

A final note about this article.  While I’m writing this for Warlocks, these new rules should apply across the board to all magic DoTs.  If you’re a caster  with DoTs – Mage, Shadow Priest, Boomkin, Elemental Shaman, Warlock, and maybe even Death Knights, though I’m not positive – these rules should now apply to you.  If you’re a class with physical damage DoTs, I’m 99% sure that Haste doesn’t affect your tick speed.  You can also still clip your DoTs (if they don’t automatically refresh).  The reasons behind it aren’t really clear to me, but I’ve been assured that this is how it works.

Basically, if your Haste is tied into your energy regeneration, you’re probably not getting any benefit to your DoTs from Haste.  And that sucks.

Because this new way of handling DoTs?  Sure, it requires some math to understand.  But the changes are awesome.

I hope all DoTs start working like this soon.

Questions?  Corrections?  Leave ’em in the comments.

Update (January 11th, 2011): Somehow, I forgot to mention that I put together a calculator for Haste Sweet Spots. If you want to toy around with your own values, give it a try!