Since picking up a Quagmirran's Eye I have noticed some odd things with the haste effect, and also have some questions regarding how it affects spells.

Does the haste proc only affect spells that start casting while it is up or can it partially speed up a cast? For example if I cast a 3second fireball while 1 second of proc is left, will that get the full bonus, or partial? Sometimes I notice that I seem to get full, and sometimes it seems like I get none at all. I haven't done any empirical testing however, so I attributed it to my mind playing tricks on me.

Basically, how exactly does spell casting work in regards to haste?

When you have the haste effect, the casttime is decreased. The tooltip should show the exact time while you have the haste effect. If you gain or lose haste while casting, that current spell would be uneffected by haste.

I just did some testing with the Blade of Wizardry (the proc is only 280 haste rating), and according to the tooltip it's cast time with the proc was 1.19 seconds. Before this I had always assume that an increase in haste rating couldn't get the cast time below the GCD. I tried to see if the proc would actually allow another spell to be cast before the GCD was up, but it's too hard to judge the .3 of a second difference.

Does anyone know of a mod that tracks cast time/GCD (or one that could)? It would be nice to know if mashing my buttons just a little bit faster actually helps when the proc is up.

As far as I knew pre-TBC, hasted Flash of Light was chain-castable. So I think spellhaste reduces GCD by the same amount as normal.
Maybe I was just lagging and unobservant though; I can't check now as I have nothing to haste with.

There's some discussion over on the mage thread in the theorycrafting section going on about haste effects, specifically spell stuff. You might want to take a look.
TBC Mage Theorycrafting

With talented Wrath (1.5s cast time) and Nature's Grace procced (-0.5s cast time), I definitely run into the GCD when chaincasting it. I'm not sure if haste effects behave the same as NG, but I would guess that they would.

Which is pretty annoying given that melee doesn't have the same issue -- one of our rogues can get sub-1.0 weapon speed on his 2.6 speed sword when he uses/procs everything at once.

Unless I'm terrible at this game it still reduces GCD.

edit: Yep I'm terrible how did I not notice that on flash of light.

Still a fan of spellhaste though, counterspell this!

I'm not going to accuse anyone of being terrible, but GCD definately seems to stay in effect regardless of haste. I use arcane blast quite a bit on pulls where we don't need alot of mana (ie trash) and with a 3stack of the debuff it's normally a 1.5 sec cast. When the quag's eye procs during this I most certainly find myself waiting on GCD to recast it.

On his autoattacks yes. They're not on a gcd, so why not? His specials will still be limited by gcd regardless of haste. What people above are saying about spell haste affecting the GCD also does not apply to hunters at all - steady shot is a 1.5s cast, and it is very very frequently reduced below that by haste effects - however it still can't be cast any more often than 1.5s because of the GCD.

I'm also greatly dissatisfied with Quag's Eye for this reason. I get lots of "That spell is not ready" when spamming Scorch (or AB on 3xdebuff) and the trinket procs, which is essentially a wasted proc. I keep only equip this if I plan on spamming Fireball alot.

Yes, not reducing the GCD is sorta frustrating, being able to throw corruption, UA, agony, and Siphon Life on a mob in 3-4 seconds would be pretty nice. When my eye does proc, it is nice to fire off a couple fast shadow bolts though. I can see this being a lot better for a demo or destro warlock who casts mostly SB/Incin instead of refreshing so many DOTs like I do and essentially wasting the proc now and then.

Heh, and I complain, game-mechanically about casters who don't have an ultimate cleave of doom or a second-aggro-you-die-now smash to worry about. Next patch can't come quick enough. :x

But the reason is we don't have cast times on our "spells", and I believe it's intended for haste to be the best raiding stat for a rogue. I'm sure if slam is used in a 2h warrior's dps cycle, he'll hit the global cooldown too. (though isn't it a 1sec cast anyway? o_O maybe that's a bad example.)

Based on my experiences and other poster's....

I think the items that do a proc (Quagmirran's Eye and Blade of Wizardry) do not reduce global cooldown.

Mana Quickening Gem and Heroism do.

---

This isn't something I've tested extensively, but based on what people are saying and my experience with heroism vs Quag's Eye and Arcane Blast.

That sounds like a rich man complaining a poor man about how hard it is to keep his money safe. We dont have the skills to spam, you do; so deal with it. I wouldnt complain if harmstring was good enough damage to use in our cycles.

Also speaking in a tanking perspective, you cant know how really frustrating it is not being able to dump that a hundred rage in the bar.

I´ve been using Quagmirran's Eye for over a month now and I can confirm that it definately does not reduce GCD. Chain casting any spell that is reduced to lower than 1.5s cast will get you error messages.

I can also confirm that heriosm/bloodlust does seem to reduce the GCD strangely enough.

Although it has been discussed before, the effect on Quag's Eye is different from Bloodlust. In the spelldat (or whatever WoW calls that) it appears to be the difference between Apply Aura: Haste (Melee, Ranged and Spell) % (lust) and spell haste rating (the blade or trinket).

I'm a big fan of spell haste conceptually but not so enamored with its implementation.

This would certainly explain the change from Classic.

I was wondering about this too tbh..

Because at one of our Gruul kills 2 weeks ago, I had both Heroism + the Quagmirrian Eye proc on me and I'm 100% positive that I didn't have any gcd at all... yep you read it right, I had 0 seconds gcd

Afaik Heroism doesn't remove the gcd completely... so either it is a bug that happens when both the haste-rating buffs from quag's eye and heroism are active, or I'm just going crazy.

I'm just curious how you managed to fit 3 fireblasts in a second, what with the cooldown on the spell.

With talents slam is a 0.5 second cast time (1.5 without talents). And yes you do run into GCD between slams. However it's nice having slam be very fast casting because that shaves off an extra second that we would have to wait before our weapon swings again (since slam resets your auto attack).

Yup.. so i'm 100% positive something very buggy with cooldowns was going on there..

I think the point he's making is that Fireblast has a 6 second cooldown (or is it 8?) no matter what. Cooldowns are not affected by haste buffs, which is why it sounds like you're either retarded or full of crap.