4) How does cooldown reduction work?
If you have 100% cooldown reduction, it does unfortunately not mean your spells have zero cooldown. 100% cooldown reduction essentially half the cooldown of a spell; for example, Explosive Blast (6 second cooldown) with 100% cooldown reduction has a 3 second cooldown, with 200% cooldown reduction it has a 1.5 second cooldown, and so on.

I'd like to know how those numbers are found. I could be missing something OVERLY obvious, so a bit more detail into the actual mechanic would be nice.

Also, why doesn't CDR and resource cost reduction reflect onto the tooltip of our spells/abilities? This may have been answered somewhere else, so sorry if it was.

i would really enjoy some clarification aswell, seeing as there is no item that gives 100% cdr these figures are a bit odd, and as far as ive known, things like cdr work off of DR, as in if you had 2 items with 20% cdr, it would reduce the spell by 20% and then reduce x number by 20% again because cdr isnt an additive stat... i.e 100 second cooldown would get reduced by 20% to 80 seconds, then get reduced by 20% to 64 seconds

Take the base cooldown and write is as "number of cooldowns per minute." (or hour or day or whatever, the specific unit doesn't matter, as long as it's consistent) Multiply it by your CDR percent as a decimal added to 1.

Example: Explosive Blast has a 6 second cooldown, which would be ten cooldowns per minute. You have 100% CDR, which we'll express as 1, and add it to 1, giving us 2. Multiply the number of cooldowns per minute by this number, to get 20. Now we can divide 60 seconds by 20 to get 3 seconds, the new cooldown.

If you had, say, 35% CDR, Explosive Blast's cooldown would be reduced to about 4.4 seconds. 1000% CDR would reduce it to about half a second.

TL;DR: Don't think of it as a percent decrease to your cooldowns, because that would allow you to remove your cooldowns entirely. Think of it as a percentage increase to how many times you can use an ability in a given timeframe. 50% CDR means you can use Explosive Blast (or whatever) 50% more times in the same timeframe than if you had 0% CDR.

Take the base cooldown and write is as "number of cooldowns per minute." (or hour or day or whatever, the specific unit doesn't matter, as long as it's consistent) Multiply it by your CDR percent as a decimal added to 1.

Example: Explosive Blast has a 6 second cooldown, which would be ten cooldowns per minute. You have 100% CDR, which we'll express as 1, and add it to 1, giving us 2. Multiply the number of cooldowns per minute by this number, to get 20. Now we can divide 60 seconds by 20 to get 3 seconds, the new cooldown.
If you had, say, 35% CDR, Explosive Blast's cooldown would be reduced to about 4.4 seconds. 1000% CDR would reduce it to about half a second.

TL;DR: Don't think of it as a percent decrease to your cooldowns, because that would allow you to remove your cooldowns entirely. Think of it as a percentage increase to how many times you can use an ability in a given timeframe. 50% CDR means you can use Explosive Blast (or whatever) 50% more times in the same timeframe than if you had 0% CDR.

Ty very much for the quick reply, makes complete sense that way. Just not what I'm used to "traditional" CDR being in games.

Would still love to know why we don't see CDR and resource reduction on our tooltips.

I'd like to know how those numbers are found. I could be missing something OVERLY obvious, so a bit more detail into the actual mechanic would be nice.

Cooldown=Nominal_Cooldown/(1+CDR). CDR in decimal, so 13% is 0.13.

I assume it's done this way to leave CDR stat at linear increase in regards to stacking, meaning that n% CDR is always of the same relative value to you, whereas if it was simply done in % reduction you'd end up with different worth of each point of CDR.

Why "bump"? These are not the official forums, no developer will ever say "yes, we will integrate this" here. If you want to request a feature, you should post this in the official forums.

You are not the first to suggest an updated tooltip though; to be honest, wizards want the *actual* resource cost (including the reduction from -resource cost items that existed from day 1) being displayed on the tooltip. No way. Nothing ever updates the tooltip, the tooltips are static and will always be independent of gear. It's part of Blizzard's "we want to keep some mechanics in the dark" mentality. Sorry to burst your (and my) bubble, but it's not gonna happen. (I would be happy to be wronged on this one though.)

Yes, to see that the tooltip reflects facts. Would be great. That way we wouldn't need guys likeVolpethropeto spoon-feed us solutions. (Great job btw).

And Bagstone, How do you find time to play the game? You write here every other minute. and thanks for that.

I will have to disagree with Volpethrope. And while I have not done so myself, I have a simple way to find out whether his vision of CDR is indeed correct or not. Let's have a look at this wand:

According to Volpethrope's formula: Slow time has 15 seconds cooldown, so it can be cast 4 times in 59.99 seconds (first at t = 0.00, fourth at t=45.00 --- technically, it will be possible to cast fifth at t = 60.00 without any CDR). Now, with the wand we will be able to have 4 * (1 + 0.5) = 6 casts in 59.99 seconds with worst roll and 6.8 casts in 59.99 seconds with the best roll on the special affix. In either case, if we have no other CDR, it is impossible to have three slow-time bubbles at once without using mirror images.

The test will be the following: someone with a good-rolled gesture (65% or more) and no other CDR at all will simply spawn bubbles as soon as they go off the cooldown. If he can get three at once without mirror images, then Volpethrope's formula is WRONG.

I myself do not know how the end-CDR is applied, but I will assume that it is done as
<default cooldown> * (1 - CDR1) * (1 - CDR2) * ... * (1 - CDRn).
where CDRk is CDR_percentage/100 (e.g. for 20% CDR, the coefficient will be 20/100 = 0.2)
This way, it is still impossible to get 0 seconds cooldown no matter how much you stack CDR.

Yeah, I just tested this. It is indeed wrong. Sigh, changing the FAQ again

20% CDR from passive and 10% CDR from paragon => 27.98% CDR. I managed to cast 11 Slow Times in 100s which translates to 9.09s ST cooldown.

Then with a 58% CDR wand; doesn't show up on character screen but according to math 69.76% CDR. Result: 26 STs in 100s, so 3.85s cooldown.

Both with considerable amount of lag, so the real values are actually even lower. The "simple formula" seems to be correct, as it yields in theory 8.64 and 3.62 as cooldown. So... yeah. It's simpler as we though.

Well, in combination with a shrine you can possibly get there already. At the end of 2.0.1 I was running 42.4%, and had something like over 70% or so with an Empowered shrine. Add the 10 minute shrine gloves to that... OP ;-)

That being said, all this cooldown reduction definitely reduces your dps, it's not for free.

source: http://www.diablofans.com/forums/diablo-iii-general-forums/diablo-iii-general-discussion/82430-2-0-1-frequently-asked-questions-and-transition-to#cdr

I'd like to know how those numbers are found. I could be missing something OVERLY obvious, so a bit more detail into the actual mechanic would be nice.

Also, why doesn't CDR and resource cost reduction reflect onto the tooltip of our spells/abilities? This may have been answered somewhere else, so sorry if it was.

Example: Explosive Blast has a 6 second cooldown, which would be ten cooldowns per minute. You have 100% CDR, which we'll express as 1, and add it to 1, giving us 2. Multiply the number of cooldowns per minute by this number, to get 20. Now we can divide 60 seconds by 20 to get 3 seconds, the new cooldown.

If you had, say, 35% CDR, Explosive Blast's cooldown would be reduced to about 4.4 seconds. 1000% CDR would reduce it to about half a second.

TL;DR: Don't think of it as a percent decrease to your cooldowns, because that would allow you to remove your cooldowns entirely. Think of it as a percentage

increaseto how many times you can use an ability in a given timeframe. 50% CDR means you can use Explosive Blast (or whatever) 50% more times in the same timeframe than if you had 0% CDR.Would still love to know why we don't see CDR and resource reduction on our tooltips.

I assume it's done this way to leave CDR stat at linear increase in regards to stacking, meaning that n% CDR is always of the same relative value to you, whereas if it was simply done in % reduction you'd end up with different worth of each point of CDR.

If anyone can find a bluepost or other information source, I'd be very interested in this...

You are not the first to suggest an updated tooltip though; to be honest, wizards want the *actual* resource cost (including the reduction from -resource cost items that existed from day 1) being displayed on the tooltip. No way. Nothing ever updates the tooltip, the tooltips are static and will always be independent of gear. It's part of Blizzard's "we want to keep some mechanics in the dark" mentality. Sorry to burst your (and my) bubble, but it's not gonna happen. (I would be happy to be wronged on this one though.)

And Bagstone, How do you find time to play the game? You write here every other minute. and thanks for that.

http://eu.battle.net/d3/en/item/gesture-of-orpheus

According to Volpethrope's formula: Slow time has 15 seconds cooldown, so it can be cast 4 times in 59.99 seconds (first at t = 0.00, fourth at t=45.00 --- technically, it will be possible to cast fifth at t = 60.00 without any CDR). Now, with the wand we will be able to have 4 * (1 + 0.5) = 6 casts in 59.99 seconds with worst roll and 6.8 casts in 59.99 seconds with the best roll on the special affix. In either case, if we have no other CDR, it is impossible to have three slow-time bubbles at once without using mirror images.

The test will be the following: someone with a good-rolled gesture (65% or more) and no other CDR at all will simply spawn bubbles as soon as they go off the cooldown. If he can get three at once without mirror images, then Volpethrope's formula is

.WRONGI myself do not know how the end-CDR is applied, but I will assume that it is done as

<default cooldown> * (1 - CDR1) * (1 - CDR2) * ... * (1 - CDRn).

where CDRk is CDR_percentage/100 (e.g. for 20% CDR, the coefficient will be 20/100 = 0.2)

This way, it is still impossible to get 0 seconds cooldown no matter how much you stack CDR.

20% CDR from passive and 10% CDR from paragon => 27.98% CDR. I managed to cast 11 Slow Times in 100s which translates to 9.09s ST cooldown.

Then with a 58% CDR wand; doesn't show up on character screen but according to math 69.76% CDR. Result: 26 STs in 100s, so 3.85s cooldown.

Both with considerable amount of lag, so the real values are actually even lower. The "simple formula" seems to be correct, as it yields in theory 8.64 and 3.62 as cooldown. So... yeah. It's simpler as we though.

That being said, all this cooldown reduction definitely reduces your dps, it's not for free.