Haste

Haste is a secondary attribute that increases attack speed, ranged attack speed and casting speed. It also increases these attributes for the player's pets, increases the regeneration rate of some resources, and increases the tick rate of most of the player's damage over time and heal over time effects. Spell haste also reduces the length of the global cooldown for spells and some melee abilities.

Prior to Patch 6.0.2, Haste occurred in a number of forms. Each of these forms of haste were displayed separately on the character sheet - under Melee, Ranged and Spell, respectively. Melee haste increased attack speed; Ranged haste increased ranged attack speed; and Spell haste increased casting speed, reduced cast time, and reduced the global cooldown. As of Patch 6.0.2, these categories have been merged, and all sources of haste now affect all 3 categories simultaneously and equally.

Attack speed and ranged attack speed increase the rate at which melee and ranged auto-attacks are dealt, respectively. This can increase the frequency and damage output of the player's auto-attacks. This can in turn increase procs from effects such as Blood Parasite and Sudden Death, as well as PPM and RPPM enchants, trinkets, and effects. Casting speed effectively reduces the cast-time of spells. This can allow casters to heal or deal damage more quickly. Non-spell cast-time abilities such as Steady Shot also benefit from haste, with reduced cast times.

Although their haste attributes are frequently unlisted, pets also benefit from haste, increasing their attack or casting speed. Pets are also affected short-term haste buffs like Bloodlust/Heroism and Mark of Warsong.

Haste also increases the rate at which players passively regenerate energy, runes, and focus. By increasing the rate of melee auto-attacks, haste can also increase the rate at which warriors and Guardian druids generate rage.

Spell haste can reduce the length of the global cooldown. For most classes, the base GCD is 1.5 seconds, and Haste can reduce it to a minimum of 0.75 second (requiring 100% haste). Reducing the GCD allows players to use their abilities more rapidly, but does not alter the cooldown of individual abilities. Starting in Mists of Pandaria, and expanding in Warlords of Draenor, many core class abilities now have their cooldowns reduced by haste (ex. Crusader Strike and Riptide). The cooldown of these haste-scaling abilities will be colored green in the in-game tooltip.

Haste also increases the tick rate of damage over time and heal over time effects. As of Patch 6.0.2, all DoT and HoT effects scale with haste. By increasing a periodic effect's tick rate, the effect's damage or healing is dealt more quickly. With sufficient haste, additional ticks will also be added, increasing the effect's output and efficiency considerably. As of Patch 6.0.2, haste's effect on periodic effects has changed considerably from previously. Periodic effects now always have the standard duration for that effect, regardless of haste levels. All periodic effects can be refreshed when less than 30% of their original duration remains with no "clipping" or duration loss (the full normal duration is simply added to the remaining duration, up to a maximum of 130% of the base duration). In addition, haste ticks no longer have breakpoints. When a periodic effect with a duration unequal to a precise multiple of the tick interval expires, a final tick will be dealt equal to the percentage of a normal tick duration that elapsed since the last full tick. For example, if a periodic effect has a duration of 15.0 seconds and due to haste has a tick interval of 2.0 seconds, it will deal 7 ticks at normal damage (14.0 seconds), then deal a final 8th tick for 50% of normal damage. This means that all periodic effects scale, in both DPS and total damage done, in a smooth manner with additional haste, with no breakpoints or jumps in benefit. In addition, like all secondary stats, haste is no longer snapshotted when the periodic effect is cast, and instead the tick interval is dynamically updated on the fly as the caster's haste varies.

Negative Haste
Players can also acquire negative haste, usually from enemy debuffs. As of Patch 6.0.2, players no longer have access to negative haste debuffs, so negative haste now comes exclusively from NPC effects.

Mobs
Mobs often grant themselves or their allies effects which increase haste. Numerous mobs have an Enrage buff that is activated when their health becomes dangerously low, increasing attack speed. Many bosses also gain haste buffs, such as Shannox or Patchwerk's Frenzy effects, either during Enrage phases or in response to specific events. While some of these effects are dispellable, many are not.

Haste rating
Haste stacks in a multiplicative manner. This means that it is beneficial to stack multiple haste effects. Haste rating stacks additively with itself (two sources of 100 haste rating give a total of 200 haste rating when stacked) and is then converted into a percentage (see table below) that stacks in a multiplicative manner with other sources of haste.

Example
A level 100 Frost mage with 1294 haste rating has the Mark of Warsong and Icy Veins buffs active.


 * Mark of Warsong grants (initially) 1000 haste rating.
 * Icy Veins increases spell haste by 30% (includes extra 10% from Improved Icy Veins).

1294 + 1000 = 2294 haste rating 2294 / 90 = 25.49% haste (1.2549) 1.2549 * 1.3 = 1.63 or 63% haste

Attack and cast time
Generally speaking, haste represents how much more of an activity you can perform in a given time. For example, 100% haste can double DPS/HPS, by allowing the player cast two spells in the time they would be able to cast one without that haste. Casting time and the auto-attack interval are therefore calculated by dividing the weapon or ability's base attack or casting time by the one plus the haste percentage.

Example
The mage above has just popped his haste cooldowns, temporarily increasing his spell haste to 63%. This allows him to deal 63% more damage or healing in a given time.

Frostbolt = 2.0 sec cast time 63% haste = 1 + 0.63 = 1.63 2.0 / 1.63 = 1.23 sec cast time

This reduces the cast-time of 2.0-second spells such as Frostbolt to 1.23 seconds.

Global cooldown
Haste reduces the global cooldown (GCD) triggered by spells and certain physical abilities exactly as it reduces the cast time of those effects, but cannot reduce it below 0.75 seconds. The length of the global cooldown can therefore be calculated using the same formula given above.

Following the above example, a mage with a Frostbolt cast time of 1.23 seconds would have a global cooldown of 1.5 / 1.63 = 0.94 seconds. Should the mage also acquire the Bloodlust/Heroism buff, his haste would be increased by 30%, reducing his Frostbolt's cast time to 1.23 / 1.3 = 0.94 seconds. However, instead of reducing his global cooldown to 0.94 / 1.3 = 0.72 seconds, it would instead only be lowered to the minimum of 0.75 seconds.

The amount of haste required to lower the global cooldown to its 0.75 second minimum is 100%. This minimum prevents players from using abilities more often than once per 0.75s, with the exception of abilities that are not on the GCD such as Counterspell, Pain Suppression and Charge. However, this only directly inhibits players' use of instant cast abilities and abilities which have had their cast time pushed below 0.75 seconds, and when combined with pushback, the availability of longer-cast spells (often serving as higher DPS/HPS or more mana efficient alternatives) and the desire to move in between casts, the minimum GCD does not necessarily prevent additional haste from benefiting the caster, though it may reduce the marginal value of the stat (see Haste Cap, below).

Tips
Because haste stacks in a multiplicative manner, it is generally of maximum benefit for players to use any haste-generating abilities or procs simultaneously. This will produce a larger benefit (measurable in DPS or HPS) than that provided if each is used separately. This is ideal for dealing with emergencies, allowing the player to rise to the occasion by significantly increasing their output on command. Most haste abilities have 2 to 3 minute cooldowns. On the downside, this approach requires the player to choose the right moment to use these abilities, and by placing many of their most powerful abilities on cooldown at once, can leave them without fallback options should events take an unexpected turn.

Since haste is dynamically updated on the fly for periodic effects, DoT/HoT recasts need not focus on haste procs any longer. However, powerful DoT/HoT abilities that are either cooldown based (eg. Divine Hymn) or have relatively low uptime (eg. Hand of Gul'dan) will have increased overall potency when used during large temporary haste buffs. In addition, while tick interval for periodic effects updated dynamically, the amount of time required to finished the cast of a cast-time ability is set when the ability begins to cast. This means that beginning a relatively long cast just as a large haste buff expires still retains the full benefit of the haste buff for that cast.

As well as increasing DPS/HPS, this can also make certain options more efficient, and therefore desirable. For example, for many Holy priests Renew is not only fairly slow, but also relatively weak and mana inefficient. By casting Renew while benefitting from haste buffs such as Power Infusion, priests can often add an extra tick to the effect, increasing output and mana efficiency by up to 25%. Since haste does not increase the effectiveness of cast-time abilities, this can shift Renew's place in the healing hierarchy from a slow and relatively inefficient heal to an efficient and desirable option. Saving haste effects for use with Divine Hymn can increase a priest's healing output significantly, and makes for an excellent emergency cooldown. Since haste increases the total potency of periodic effects while decreasing the time necessary to use them (whether that's a cast time or a GCD), the damage or healer per time spent casting goes up significantly faster for periodic effects than it does for direct damage effects.

Perhaps the most well-known of all haste buffs are the raid-wide Bloodlust/Heroism, Time Warp and Ancient Hysteria. With a 5-minute cooldown and a 10-minute debuff, timing and coordination are required to make the most of these powerful buffs. Using them in less than critical moments may not only waste your own cooldown, but also prevent others in your raid from using them when they are needed most.

Haste cap
While there is no point at which haste becomes entirely unbeneficial, different classes may find it becomes less valuable at a certain level. In practice, haste is restricted by gear and effects, and does not exceed certain levels outside of special encounters (such as "Captain" Cookie in the Deadmines). The most significant cap for haste is the point at which its acquisition requires the trading of something more valuable, whether a superior talent, or a disadvantageous amount of a critical attribute.

Haste cannot reduce the global cooldown below 0.75 second. Thus, once a player has enough casting speed that all of the abilities they use in combat have a casting time of 0.75 second or less, additional haste rating won't increase their damage per second or healing per second from abilities (even on fights that are too short for mana to become the limiting factor). For some casters, this can be seen as a "haste cap". However, even above this point additional haste has its benefits, such as allowing the use of abilities with longer cast times. For example, sufficient haste would allow a priest to use Heal rather than Flash Heal, saving a large amount of mana. Also, additional haste will still reduce the actual time spent casting, which can be advantageous when making split-second casts, avoiding interrupts or trying to move between casts. When dealing with spell pushback additional haste can be very useful, potentially granting the caster an effective immunity to pushback, due to 'excess' haste counteracting its effects.

In most respects haste does not have a cap; haste rating does not suffer diminishing returns, and most of its effects continue to increase in a linear fashion. For melee types (and hunters), since auto-attack speed does not have a limit, haste will continue to increase DPS, as well as generating additional talent procs and resource generation/regeneration rate. HoTs and DoTs can likewise be extended by several ticks, dramatically improving efficiency, speed and output. Many periodic effects (such as Shadow Word: Pain and Vampiric Touch) effectively do not have a haste cap, and can be improved with haste to deal damage more than once per second. Some other effects cannot tick faster than every 1 sec, and so effectively have a haste cap of just under 200%, but this is unlikely to be reached very often.

The most important question for haste stacking is its relative important to your class, spec and playstyle. Some classes rely heavily on haste to improve their DoTs or their auto-attack speed, while for others it is of minimal importance, and should be avoided wherever possible.

Patches and hotfixes

 * Periodic effects no longer snapshot and no longer have breakpoints. Rating conversions were squished.
 * Periodic effects no longer snapshot and no longer have breakpoints. Rating conversions were squished.