Is there such a thing as a haste cap?
I wouldn't have even thought of this question until last night when I was guild raid in Naxx 25 for a break from ulduar and a new mage asked me what my haste was. Uh... 597 atm, why do you ask? He replies not to tell me how to play my character but I may want to consider replacing my JC gems for SP since the haste cap for moonkins is 400. He said he got this info from EJ but I can't find any mention of it even in the haste mechanic forums. By no means do I mind switching out 81 haste for 93 spell power IF the cap is as that guy suggested (btw he says his main is a moonkin on another server). Also, when he said 400 the number flipped a switch in my brain because I remember watching a video on Foofy's Cupcake Factory that lists a 400 maximum for haste if you are using the Solar rotation - but I could never figure out why she gave the number of 400! So confusing >.<
So in the end maybe I just overlooked someone in one of the forums or another moonkin site of the 400 spell haste cap for us but I am just not sure enough to change out my gear (I have crit heavy gear I can switch out in my bank to get closer to that 400 number). Can you help me?
Yes, there is a Haste cap for moonkin, but it is not a hard cap like Hit rating.
The Global Cooldown (GCD) starts at 1.5 seconds, but has a minimum value of 1 second. The cast time of any spell can technically go below this level, but you can't cast a spell while in the GCD so the affective minimum cast time is 1 second.
So, when people refer to the Haste Cap they are referring to the level at which a spells cast time goes below 1 second. This primarily affects instants and spells with short cast times like Wrath. Spells with long cast times like Starfire are rarely impacted if ever.
Assuming that you have Celestial Focus (3%), Improved Moonkin Aura (3%), Wrath of Air (5%), and Natures Grace (20%) up. Then you only need 12.21% haste from gear to reach the cap. (1.5/(1.03*1.03*1.05*1.2) = 1.122138) Since it takes 32.79 to get 1% haste you can see that 400 haste will get you the 12.21% you need. Therefore the Haste Cap for Wrath is 400 Haste Rating.
For Starfire with the same buffs the Haste cap is 4080. If you add Heroism/Bloodlust it drops to 2382. Obviously, these levels are unreachable except in the rares of occasions. Therefore, you don't need to worry about the SF haste cap.
The Haste cap only really matters if you use a Solar rotation. If this is the rotation you use then after 400 you should focus on Crit a little more then Haste. Haste will still have some value because SF is still a part of your rotation and NG won't have a 100% uptime, but its value is significantly reduced. Basically, If your using a Solar rotation you don't want to stack haste beyond 400, but you don't want to avoid it at all costs either.
If you use a Lunar rotation there is no real reason to worry about the Haste cap. Haste scales very well with Starfire for all reasonable levels of gear currently available. Since Starfire is your primary spell in a Lunar rotation Haste works very will with it also. Yes, Wrath is a significant part of a lunar rotation as well, but it isn't enough to devalue the stat to below Crit Rating.
Gemming for Haste:
I want to say a quick thing about gemming for haste. The only time I would ever gem for haste is if it is a yellow socket and I wanted the socket bonus. In which case I would socket a Reckless (SP/Haste) gem. Other then that, it is never a good idea to gem for haste.
In The Burning Crusade there was a point where Haste became more powerful in terms of DPS then Spell Power. On top of that we were able to raise our Spell Power levels so high that at some points it made sense to gem for haste instead of Spell Power. That point currently does not exist in Wrath of the Lich King.
How we play a moonkin in WotLK is very different then how we played our Moonkins in TBC. In TBC we basically Starfire spammed and refreshed Moonfire when it dropped off. This was great for haste because SF and Haste work so well together. On top of that, we weren't able to get any significant amount of haste gear until ZA and Tier 6 came out. So our Spell Power levels got very high while our haste levels remained very low. Neither of these facts are true for WotLK.
In WotLK, Wrath is a significant part of our rotation, and haste has a very limited value for Wrath after 400 haste rating. On top of that, we are able to picking up tons of haste gear from quest rewards and Heroics. Combine this with the fact that the itemization cost of Haste is still higher then that of Spell Power and you can see how the break even point for Haste and Spell power is pushed out of reach.
1. If you use a Solar rotation then the cap is 400, but don't worry about going above it. Haste still has some value.
2. If you use a Lunar rotation don't worry about a haste cap at all. You can't reach it for long periods of time.
3. Don't gem for Haste unless you have a yellow socket and you want the socket bonus. In which case use a Reckless Gem that provides both Spell Power and Haste Rating. Don't eat haste food either.