GCD and almost-instant casts

[zakaluka]

My GCD is 1.2 seconds after cast time reduction from haste.

However, minimum GCD is 1.0 seconds so with Rapid Renewal, Renew loses any cast time benefit from haste (still gets the 5th tick though). No matter how much haste you have, gcd for Renew is still 1.0 seconds. Meaning renew is once again behind PoH for hpct at high haste rating (sigh).

Now this brings me to an interesting question, what about almost-instant spells (sanctuary, mass dispel)?

Nothing in the tooltip suggests the GCD is reduced, so: do these spells still eat up a 1.2 second GCD despite the very quick cast, or a 1.0 second GCD? I know the GCD is longer than cast time, because I can't que another cast on top of MD or Sanc.

[Deleted]

you still have the GCD. if the cast is shorter than the GCD then you just have some 'dead' time between the end of the cast and the start of your next cast. You can use it for moving I guess.

[Wuga]

Yeah, every spell (except those off-GCD or modified by talents like renew/rejuv) consumes the same length GCD regardless of cast time.

[TheTrueM4gg0t]

jap. every spell that is on the GCD has 1.5sec GCD. can be modified by haste and talents, but cannot go unter 1sec. (GCD is independant of casttime, and thus applies to 0.5sec casts as much as it does to 3.5sec casts)
thats how it works for casters, melees rules are different (depending on class)

[Danner]

From the time you press any ability button, the GCD will be triggered. During this period, you cannot click another ability button. If the spell cast time surpass the GCD, you will not actually notice the GCD, but it is there. If the spell cast time is less than the GCD (lightwell etc) the remainder of the time will be spent as GCD time. This may seem pointless, but the major difference is that you cannot be interrupted/pushbacked in this excess period of time. With extreme haste, you can lower the GCD down to 1 second, but you cannot get it below that no matter what haste levels you have.

The GCD is mostly there to reduce extreme server traffic. But it has been admitted that maybe pushing many buttons isn't that big a deal for server traffic after all, so some future expansion may just completely redesign how it works. Interestingly enough, the GCD is a client side cooldown. The client has an anti-lag feature which allows you to cast the same spell again up to 0.3 seconds before the GCD is up. As a priest, you can notice this by spamming Flash heal. You can cast the next Flash heal prematurely, but you will have to wait the full GCD before casting say a Prayer of Healing. Even if you do manage to send off a spell faster, the server will just queue it up though, so the only time you save is network transmission time. But that's not a bad deal.

There are some exceptions to the GCD rule.

If your spell affects the next spell directly, it will generally not be affected nor trigger the GCD. For priests that in particular mean Inner Focus. But also Guardian Spirit is exempt from both being blocked and triggering the GCD. Pain supression is not so lucky (at least last time I checked).

Blood Elves can also use their Arcane Torrent racial without triggering or be blocked by the GCD, but Tauren's warstomp will be blocked by the GCD (but not trigger it). Some onuse trinkets also do not trigger the GCD, other do, but in general they are all affected by it. It's a bit of a mess really.