Truncheon (20% death) + Grim Cesta(20% death) Are they stack?

I know that there are two collector items as follow.

Truncheon, Cold Dmg: 11-22 (req. 9 Death Magic)
Halves skill recharge using Death Magic skills (20% Chance)

Grim Cesta, Energy +12 (req. 9 Death Magic)
Halves casting time using Death Magic Skills (20% chance)
Halves skill recharge using Death Magic skills (20% chance) .

The questions is that :
If both items equiped, the skill recharge will be

a) halved still at 20% chance?

b) halved at 40% chance?

c) halved at 1.2x1.2-1 = 44% chance?

d) most complicated (using conditional probability and tree diagram):
no change : 08*08 = 64%
halved : 08*02+0.2*08 = 32%
1/4 : 0.2*0.2 = 4%

which case is correct?

Wow you got me there dude.

I run with a MM both of these and I've noticed empirically that they stack. So you get faster recharge 40% of the time.

Yeah, that's it, and I'm sticking to that until someone proves me wrong.

Of course you could just equip both and go outside and try it. Cast 5 Death spells in a row. Not the recharge results. Repeat this experiement say... 20 times. Note the results. You should have a reasonable idea though it might be hard to distinguish between 32% and 40% with such a small data set.

none... i saw an equation someone on this thread did one time about it, which sounded really good, but was incorrect, with his final conclusion of 36%.

because anyone with a bortaks set or stacked mods, knows it doesnt just "halve" the casting time (or recharge in ur case) more, it "halves the half" sometimes too.... like with bortaks, with is 20 and 20 on casting, sometimes u get a nice quick cast, which is half of the original time (3 seconds for Fiend raising, and for simplistic purposes, just say u dont have bloodstained boots on), which is 1.5 seconds. but then once in awhile, u get that lightning quick cast, which is much shorter than 1.5 or 3 seconds, becuz its the extra 20% kicking in, so u end up casting in .75 seconds (half of 1.5).

so yes, it does stack, just not what ur thinking of. it literally "stacks" in the most literal definition of the word (half of half).

as far as it COMBINING, like getting regular half casting 36-40% of the time or whatever, i'm not sure. it seems like it does that too, maybe as one is taking effect and the other isnt. since u got 2 of em, it happens more often than if u had one mod. and sometimes, as i described above, they both take affect at the same time, to give the half of half casting or recharge.

Actually this does sound more like what happens. Sometimes the recharge is normal and other times it's lightning fast or something inbetween.

Maybe it's something like this?

What is the probability of getting a fast recharge: 2/5 or 40%
What is the probability of getting an ultra fast recharge: 2/5 * 2/5 or 4/25 = 16%

I could be wrong about the last part because the events may not be considered to be independent. If that's the case then it would really be this:
What is the probability of getting an ultra fast recharge: 1/5 * 1/5 or 1/25 = 4%

It stacks, but not as 20+20=40

Here's how it works:
You have a 20% recharge weap for Death Magic and 20% recharge offhand for Death Magic also.

You cast a death magic spell, let's say initial recharge is 10 seconds.

Initial recharge = 10s

With your weapon, you have 20% chance to halve that. If you do get the fast recharge bonus, recharge time is now 5 seconds, if you don't, it stays 10s.
Now, your offhand. You have 20% to halve the current recharge time. If you get lucky, managed to halve it on the first time and halve it again, your spell will recharge in 2.5s. If you didn't manage to halve the cast time earlier and now do, it'll recharge in 5s. Otherwise, it recharges in 10s.

Cerb is by far a better expert than me and has more empirical experience so I'd go with what he says.

One thing this makes me realize is that taking two 20% items for recharge is great for getting a fast cast, but if you're bringing it for ultra fast casting you're wasting your time.

The correct answer is option D by the OP.

Quote: Originally Posted by Carinae Dragonblood