Some questions about spell haste rating.
 

Hello there, as the topic says I have a few questions about spell haste rating and I would love it if you took some time to answer them.
I've tried searching but either I'm retarded or there isn't a lot posted about since the 2.1 patch which made some changes to it, or so I hear.

First of all I wonder how much the cast time is decreased per rating, I read somewhere that it was about 15 rating to reduce cast time with 1%, but this was a really old post and I don't think it's true for 2.1.
Secondly, people have suggested to me that spell haste affects Global Cooldown, is this true?
The last thing I would like to know is if it affects channeled spells like arcane missiles or mind flay?

I don't have much spell haste gear availible to me so I can't really try things out for myself, instead I have to bother you guys :)

As of 2.1, I'm not sure if anyone's taken the time to check whether or not Spell Haste is decreasing the global cooldown. Pre 2.1, it didn't.

However, effects such as Bloodlust/Heroism *will* reduce the GCD.

Lastly, as of 2.1, Spell Haste now properly affects channeled spells. Your channeled spells will have their 'duration' shortened, while still doing the full amount of they are supposed to.

First of all I wonder how much the cast time is decreased per rating, I read somewhere that it was about 15 rating to reduce cast time with 1%, but this was a really old post and I don't think it's true for 2.1.

I'm not sure, but assuming that post was accurate pre 2.1, it would be 10-12 haste rating per 1%.

Secondly, people have suggested to me that spell haste affects Global Cooldown, is this true?
No. However, with client lag, often times people are well done with casting a spell before the client reports it, so they hit the next spell "early" because of spell haste, when in actuality they are merely closing the gap between the two spells. It's half-psycholigical, half due to GCD visually being client side and the check being server side. If you have 1.2 second casts that means .3 seconds where the GCD is restricting casting. Because of human reflex or just poorely timed casting, people may cast sooner with spell haste and cover that innate gap. It's like cleansing a fear before it is actually cast.

The last thing I would like to know is if it affects channeled spells like arcane missiles or mind flay?

Yes, as of Patch 2.1.

Spell haste does -not- affect the Global Cooldown. Effects such as Bloodlust/Heroism do but the same is not true of spell haste.

It does affect channelled spells, this change was made in 2.1.

Hope that helps.

Thanks a lot for the quick replies, I really appreciate it.