Faster Casting

Would like to know the math behind Faster Casting. I'm thinking of putting Spell Totem with Faster Casting and some other spell (let's call it X for now).

Let's assume Faster Casting's at level 1, with no extra quality (20% increased cast speed). Spell Totem reduces cast speed of the spell by 30%. How is the final cast speed calculated?

Would it be:

"

1.00 - 0.3 + 0.2 = 90% cast speed

or would it be:

"

0.7 * 1.2 = 84% cast speed

I'm assuming that Spell Totem's 30% reduction is always taken into consideration first, seeing that it is the one casting the spell, while Faster Casting is the support (weird, seeing that Spell Totem itself is a support spell as well) here, but I could be wrong. Also, how does cast speed passive skill nodes get added into the calculation (again, a question of whether it adds to the sum, or it multiplies)?

reduced is not multiplicative (less is but thats not here).
so it is: basespeed *(1 -0.3 +0.2) -> base *0.9

"

soul4hdwn wrote:

reduced is not multiplicative (less is but thats not here).
so it is: basespeed *(1 -0.3 +0.2) -> base *0.9

Great, thanks a lot!

Faster Casting is currently bugged with Flame Totem. At level 1 it works fine, it increases the totems casts per second by 20%, but levelling up the Faster Casting gem has no effect on the totem's cast per second rate.

[edit]: It's working correctly now. @Vipermagi: 1% is enough to make a difference, the casts per second is calculated to two decimal places.

why does faster casting still work with auras? It unnecessarily increases the aura's cost. Even when linking spell totem with auras, 2.0 made it so that faster casting doesn't affect totem placement speed.

Please change this gem to do more cast spead instead of increased to align the benefit with other often used support gems.
I think, it's currently used for levelling and movement skills only and way inferior to Spell Echo which will also have it's Plus verion soon.