I wanted to pull some of the discussion on haste out of the Anub thread. Also, since this topic comes up from time-to-time, I thought it would be good to put the collective wisdom together in one place.

So... if you know what's going on with haste, soft caps and "diminishing returns" please post your summaries.

Here's a few obvious questions:

1. Does haste benefit some spells more than others
a. instant-cast
b. HOTs and DOTs
c. Channeled

2. What is a soft cap?

3. How does haste have Diminishing Returns?

1. Does haste benefit some spells more than others
a. instant-cast--only efect gcd
b. HOTs and DOTs--as of now don't tick faster, only effects their gcd
c. Channeled--channeled faster for full dmg

2. What is a soft cap?--getting the gcd to 1s is the soft cap, 1s is as low as it goes

3. How does haste have Diminishing Returns?--there is no point getting casts below 1s because then you are still waiting on the gcd

note: I don't think I've ever used haste so feel free to correct anything.

What Riot said is exactly how I understand it. I don't know how it affects trees with the talent that reduces the gcd on instant casts, if at all.

1. Spell Haste Rating

Spell Haste Rating increases the casts of the spell per minute. So the formula for calculating the exact cast time is as follows:

New Casting Time = (Base Casting Time)/(1+(% Spell Haste/100))

The generally agreed upon conversion is 32.79 haste rating = 1% of spell haste.
Since patch 3.1 Death Knights, Druids, Shamans, and Paladins get 25.21 haste rating = 1% of spell haste.

Basic Chart of Spell Haste effects on a 3 second spell:

% Haste	Cast Time	CPM
0%	3 sec	20
10%	2.73 sec	22
20%	2.5 sec	24
30%	2.31 sec	26
40%	2.14 sec	28
50%	2 sec	30
60%	1.87 sec	32
70%	1.76 sec	34
80%	1.67 sec	36
90%	1.58 sec	38
100%	1.5 sec	40

The CPM (cast per minute) is linear increase, but the reduction on spell cast has diminishing returns per % of haste.

2. Global Cooldown

Global Cooldown is 1.5 seconds and can be reduced to 1 second with 50% haste. If you have over 50% haste then your cast time will still be reduced, but you might have to wait for the global cooldown to cast again.

This table explains what spells can benefit from over 50% spell haste and are not being restricted by the GCD cap.

Spell Cast Time before Haste	Benefits from over 50% haste	Benefits from 100% haste
>= 2 secs	yes	yes
>1.5 secs and < 2 secs	yes	no
<= 1.5 secs	no	no

3. Raid Buffs

Certain Raid Wide buffs grant spell haste.

Constant:
Ret Paladin(Swift Retribution) or Moonkin (Improved Moonkin Form) 3%
Wrath of Air Totem 5%

Short Duration:
Bloodlust - 30%

	% haste to get 1 sec GCD
constant	42%
w/ Bloodlust	12%

4. Spell type benefit

Spell Type	Haste Improves
Instant Cast	GCD only
Spell with Cast Time	Cast Time and GCD
HOT or DOT	GCD benefit only, 3.3 might give more
Channeled spell	Channeled faster for full damage

5. Class Soft Cap to reach 1 second GCD

Healer Classes:

Class	Haste from Talents	% Haste needed	Haste Rating needed
Holy Paladin	Judgement of the Pure 15%	27%	682
Priest	Enlightenment 6% Borrowed Time 25%	11%	361
Shaman	0%	42%	1059
Druid	Gift of the Earthmother 20% Nature's Grace 20% Celestial Focus 3%	14%	359

DPS classes:

*need better numbers for some of these classes*

Class	Haste from talents	% Haste needed	Haste Rating
Mage	Netherwind Presence 6%	36%	1180
Warlock	Eradication 6% Grand Spellstone 7.3%	29%	951

Thanks Janthu!

I think there's an error (or something I don't undertand) in your table #2.

Should it not be >= 1.5secs?

Cast Time before Haste	Benefits from over 50% haste
>= 1.5 secs	yes
< 1.5 secs	no

It takes 50% haste (about 1600 haste rating, or some combination of haste rating, auras etc.) for an instant cast (1.5s GCD) to get down to the 1.0s GCD minimum.

janthu has it mostly right. let me add some druid-specific items (mostly tree-ish, phoof or dove will have to contribute for boomkins).

in your item 5, janthu, 22% isn't necessarily right for druids for all spells.

we have a tier 10 talent in the resto tree, Gift of the Earthmother (GotEM), which has 5 points available:
Reduces the base global cooldown of your Rejuvenation, Lifebloom and Wild Growth spells by M%.
where M is currently 4/8/12/16/20% for the 5 points. all trees take this, however many points are necessary to get your GCD on those 3 spells as close as you can to 1 second (see table below). no boomkins take this, as it's too deep in the resto tree.

we also have 2 haste talents in the balance tree. first is a tier 3 talent that is often taken by trees (and all boomkins of course), Nature's Grace (NG), which has 3 points available:
All spell criticals have a N% chance to grace you with a blessing of nature, increasing your spell casting speed by 20% for 3 sec.
where N is currently 33/66/100% for the 3 points.

second is a tier 4 talent that is not normally taken by trees, but is taken by boomkins, Celestial Focus (CF), which has 3 points available:
Reduces the pushback suffered from damaging attacks while casting Starfire, Hibernate and Hurricane by X% and increases your total spell haste by Y%.
where X and Y are 23/46/70 and 1/2/3% for the 3 points. some trees are taking this talent for the anub fight.

the important thing for trees is when you can start dropping points out of GotEM, since we're mostly healing with those 3 HoTS. the following table shows that (*not* assuming any points in CF):

Points in GotEM	Haste needed to reach 1 sec GCD	Haste with WOA totem and boom/ret aura
5	505	359
4	688	541
3	890	723
2	1113	905
1	1362	1086
0	1640	1268

so, assuming we have WOA totem up, and there is a boomkin or pally in raid, then if you reach 541 haste, you can drop a point out of GotEM and still have the GCD on the 3 HoTS be 1 sec.

note that spells other than the 3 HoTs (including Healing Touch, Nourish, and Regrowth) still benefit from haste above the soft cap in the above table. in addition, Remove Curse and Abolish Poison also benefit from haste greater than the above levels.


EDIT: the 3.3 patch is going to nerf GotEM to the ground, and is causing extreme consternation in the EJ tree forums. the nerfed levels will be 2/4/6/8/10%, which is going to cause us to stack incredible amounts of haste to get to the soft cap.

Boss:

Table 2 should be clearer now

Roto:

Yeah I don't understand the math on Resto Druids yet. NG = 20% and GotEM = 20% so you should only need 2% to get soft capped which is 51 HR, but none of the numbers work out that way.

Are they assuming 10% average spell haste due to the crit mechanic?

I put your numbers up in the chart, but I don't really understand where they get that number yet.

in "normal" healing, NG is never up for us, because our HoT crits don't proc it. in fact, our HoT ticks used to never be allowed to crit at all, the ability of Rejuv ticks to crit is a brand new mechanic, but those crits don't proc NG. NG only procs on Regrowth, Nourish, and Healing Touch.