This is short explanation how Blizzard is changing Damage of Time effects in Warlords to remove all haste breakpoints. It’s based on explanations Celestalon gave here on twitter. Most of it should apply to HoTs as well, though those HoTs that have a initial tick might be a little bit tricky.
Currently every DoT class needs to be aware of their dots breakpoints. For Warlords of Draenor Blizzard is removing all breakpoints. 20% more haste will be twice as valuable as 10% haste. Also the duration of all DoTs won’t change with the amount of haste you have. Frankly that’s all most players need to know about DoTs in Warlords.
But for those who might have read about partial ticks or are curious how exactly Blizzard is achieving that, read on!
Let’s start with a simple dot/hot that has a duration of 12s and ticks every 3s. So we get 4 full ticks. I have a fancy graphic for you. In that graphic the red bar is the duration of DoT, the blue bars are each tick. And obviously the first tick is after 3s.
Up until late Wrath of the Lich King haste only affected the global cooldown, if I recall that correctly. There’s some benefit to a reduced global cooldown, but for the rest of this blog post I’ll ignore that aspect of haste.
Also let’s assume that each tick does 300 damage, then 4 ticks a 300 damage is 1200 damage. Meaning the dot has 1200 damage per cast or 100 damage per second. So far so easy. In a 6 minute fight, keeping the DoT up on one target uses 30 global cooldowns.
Now let’s add 20% haste, that increases the tick rate to every 2.5s. In the current model which is in use since Cataclysm, every DoT always has a whole number of ticks. The duration (12s) is divided by the tick rate (2.5s) and then rounded to the next whole number. Thus for 20% haste, we get 12/2.5 = 4.8 rounded to 5 ticks. Thus the duration of the DoT is modified to 5 * 2.5s = 12.5s. The haste level at which you gain such a additional is called a haste breakpoint and if you are a caster you surely know your haste breakpoints.
So we get 5 ticks a 300 damage in 12.5s. That means we have 1500 damage per DoT cast, which is 25% more than the DoT without haste and 120 damage per second, which is 20% more than the DoT without haste. Also in a 6 minute fight the DoT needs to be refreshed 29 times.
Let’s compare that to 9.1% haste, which gives a tick rate of 2.75s. Since 12/2.75 is less than 4.5, we get 4 ticks a 300 damage in 11s. That means we have 1200 damage per cast, which is no change to having no haste and 109.1 damage per second, which is 9.1% more than the DoT without haste. Also in a 6 minute fight the DoT needs to be refreshed 33 times.
By going from 9.1% haste to 20% haste, our damage per second increased linearly just like it should. But the damage per cast was not affected by the low haste number and 20% haste increased it by 25%. Also at 9.1% haste instead of using 30 global cooldowns, we need to use 33. And at 20% haste, we are using 29. It’s a odd system. It’s all caused by rounding the number of ticks.
If you didn’t understand my explanation, Hamlett explained it here too. He has even fancier graphics!
In Warlords of Draenor the rounding is removed, instead there are partial ticks. That is in the 20% haste case, that was with 2.5s tick rate, we simply get 12s / 2.5s = 4.8 ticks. That is 4 full ticks and one 0.8 tick at the end. The duration of the DoT is not affected by haste anymore.
Take a look at his image:
The last blue bar is the partial tick, it deals only 0.8 * 300 = 240 damage.
That means, with 20% haste we now have: 1440 damage per cast, 120 damage per second. And since the duration is unaffected by haste, we always need to use 30 global cooldowns. The 20% haste increases both the damage per cast and damage per second linearly. And that’s true for all haste levels. It’s awesome.
There’s only thing left to explain, and that’s refreshing the DoT and what happens to the partial tick in that case. It’s very simple, take a look at this, which shows the same DoT but refreshed once.
That bar is 24s long, and there are ticks every 2.5s. That gives us 24/2.5 = 9.6 ticks, that is 9 full ticks and one partial tick of 0.6 * 300 = 180 damage. Thus the DoT dealt 2880 damage, which is exactly twice as much for twice as many casts and seconds.
You might wonder where the partial tick went. Take a look at the next image. I colored the duration that was added by the refresh in a darker red.
Now you can see that the first tick of the second duration is after 0.5s. If a DoT is refreshed, instead of the partial tick, the first tick of the second duration is earlier. That’s why there are not 8 full ticks, or twice as many as in 12s, but 9 full ticks.