Note: This guide was written well before WotLK as released. The information and modeling done here is based completely on a BC version of WoW. While I thing this information is still generally correct, It does not apply direct any more. I do plan on writting a new guide and will post on my blog when it is done.
Spell Haste is the most misunderstood stat within the Moonkin community. If you watch the WoW druid forums regularly you see plenty of Spell Haste questions. The sad part about his is many of the people answering these questions provide incorrect or miss leading information. With this post I hope to provide the answers providing the Pros, Cons, and Breakeven points of Spell Haste.
1. Spell Crit is excluded from the calculation due to the fact that it affects Spell Damage and Spell Haste equally in terms of DPS. I ran the numbers with several levels of crit and the ratio between Spell Damage and Spell Haste is the same for all levels of Spell Crit used.
2. Spell Hit is excluded from the calculation due to the fact that it affects Spell Damage and Spell Haste equally in terms of DPS. I ran the numbers with several levels of hit and the ratio between Spell Damage and Spell Haste is the same for all levels of Spell Hit used.
3. This analysis has been written using Starfire but all moonkin spells are very similarly affected by Spell Haste. Therefore this analysis can be applied to Wrath and other Moonkin Spells.
4. Calculations assume that the caster is level 70.
Talents and other Buffs Affecting Spell Haste:
There are several items and spells that temporarily buff haste, but none of these last longer then 30 seconds. Therefore they will be excluded from the calculations.
General Spell Haste Info:
* Spell Haste lowers a spells casting time and lowers the global cooldown. Haste cannot lower the global cooldown below 1 second. However it would take 785 Spell Haste to lower the global cooldown to 1 second. This level is not possible to achieve long term with gear currently available in game.
* Spell Haste has no affect on the damage caused by a single spell. It only changes the casting time.
* Spell Haste has diminishing returns. Your first point of Spell Haste will affect your cast time more significantly then your second point.
* Cast Time Calculation: Base Cast Time / (1+(Spell Haste / 1570)) = Actual Cast Time. Ex: 3.0 sec / (1+(157/1570) = 2.73 sec for Starfire with 157 Spell Haste.
As with all of the Spell DPS stats the value of Spell Haste and Spell Damage are highly dependent on each other. Obviously the amount of DPS you gain from one point of Spell Damage increases the more Spell Haste you have since Spell Haste will decrease your cast time. The amount of DPS you gain from one point of Spell Haste increases with the amount of Spell Damage you have because Spell Damage increases how much damage your spells do per cast.
How much additional DPS will you receive from an additional point of Spell Damage?
Moonfury, Wrath of Cenarius and your Spell Haste all affect the amount of DPS you gain from Spell Damage. Starfire has a base Spell Damage Coefficient of 1, and let X equal your Cast Time. So the additional damage from one point of Spell damage is:
Damage = ((1 + 0.2)*1.1)/X, So if you have zero haste Then
Damage = ((1 + 0.2)*1.1)/3.0
Damage = 1.32/3.0 = 0.4400 DPS per point of Spell Damage with zero Spell Haste.
How much additional DPS will you receive from an additional point of Spell Haste?
First we need to figure out how much DPS Starfire does on a normal cast. It has two components, base spell damage and bonus spell damage. Base spell damage is the damage that comes with the trainable spell with no bonus from gear. A max rank Starfire can hit for between 550 and 646. It is increased by 10% because of Moonfury, so the average base spell damage for Starfire is 657.8. Bonus spell damage is what you receive from gear and is calculated on your character screen. It is modified based upon the base casting time of the spell and talents. Starfire has a Spell Damage Coefficient of 1, and it is modified by Wrath of Cenarius and Moonfury as I said before. Of course all of this need to be divided by your Spell Cast Time. So the DPS of your average non-miss Starfire is equal to:
DPS = (657.8 + (Spell Damage)*(1 + 0.2)*(1.1)) / Cast Time
DPS = (657.8 + (1100)*(1 + 0.2)*(1.1)) / 3 = 703.2667, If you have 1100 Spell Damage and zero Spell Haste.
Now, if we had one point of Spell Haste to the equation then we increase the average DPS per spell cast. Using the equation
DPS = (657.8 + (Spell Damage)*(1 + 0.2)*(1.1)) / Cast Time
DPS = (657.8 + (1100)*(1 + 0.2)*(1.1)) / (3/(1+(1/1570))) = 703.7146, If you have 1100 Spell Damage and zero starting Spell Haste.
So from one point of Spell Haste you gain 0.4479 DPS with 1100 Spell Damage and zero starting Haste. Lets compare this value to the DPS value I calculated for one additional point of Spell Damage.
0.4479/0.4400 = 1.0180
So, at 1100 Spell Damage and zero starting Haste, one additional point of Spell Haste is worth 1.0180 points of Spell Damage.
I have calculated this value for several levels of Spell Damage and Spell Haste. Here is a graph that shows the results.
As you can see from the graph above the value of Haste is below that of Spell Damage ever for some reasonable amounts of Spell Damage. Not only that, but as your starting haste increases the value of an additional point of haste decreases relative to Spell Damage.
This brings up two important questions. When should you start picking up haste? How much haste is too much haste? If we ignore the mana concerns that come with Haste, these questions are very easy to answer from a mathematical standpoint.
When should you start picking up haste?
Assuming that you are starting with zero Spell Haste, one point of Spell Haste, will provide more additional DPS then one point of Spell Damage when you have 1,072 Spell Damage fully raid buffed. This is a fairly easy level to reach if you uses flasks and other consumables, but hasted should not be equipped before you reach this level.
How much haste is too much haste?
Unlike Spell Hit, there is no reasonable level of Spell Haste where Spell Haste becomes worthless on its own. However, if you collect to much Spell Haste you can push its value below that of Spell Damage as we can see from the graph above. You can find this break even point with a simple equation.
Spell Damage > Spell Haste + 1,071
If that equation is correct for your toon, then you do not have to much haste. So for example, if you have 75 Spell Haste, then you should have at least 1,146 Spell Damage fully raid buffed.
Gemming for Spell Haste:
Another very common question is when should you gem for spell haste. And it is a little more complicated to answer. It depends on stat your not gemming because your gemming haste, and what quality of gems you are using. Lets look at each of the stats and see how they affect the choice.
Spell Hit – Assuming you are not hit capped. Spell Hit is always more valuable then Haste. If you are not hit capped do not gem for Haste.
Spell Crit – Spell Haste will always improve your short run DPS more then Spell Crit. My math showed that Spell Haste was better then Spell Crit even if you had very low crit and very high haste. So don’t be afraid to put a Reckless gem in those yellow sockets instead of a Potent gem if your above the break-even point.
Spell Damage – This is the complicated one. Unlike the other stats Spell Damage has a lower stat value then Spell Haste. So you will get more Spell Damage on a gem then you will Spell Haste. For Example The Runed Crimson Spinel will give you 12 Spell Damage. The Quick Lionseye on the other hand will give you 10 Spell Haste. So right off the bat Spell Damage has a 1.2 greater value then Spell Haste. This cause us to have a different break-even point when gemming for Spell Haste over Spell Damage. It is:
Spell Damage > 1.2 * (Spell Haste) + 1,386
If that equation is correct for your toon, then you can gain more DPS by gemming for Haste instead of Spell Damage. So for example, if you have 75 Spell Haste, then you should have at least 1,476 Spell Damage fully raid buffed before you gem for haste over damage.
1. My results show that moonkin shouldn’t consider equipping haste until they have at least 1072 Spell Damage raid buffed. This however is an absolute minimum and higher levels of Spell Damage are recommended to be safe.
2. You can always gem for Haste over Spell Crit to increase your DPS, but should never gem for Haste over Hit if you are not hit capped.
3. You need at lease 1,386 Spell Damage raid buffed to gem for Haste over Spell Damage, but should probably have significantly more.
4. This whole article ignores the mana issues associated with Haste. If you find that you are running out of mana at the end of long fights then you should probably hold off on equipping haste until your mana situation is more stable.