Spent some time in the College of Magic experimenting with magic (appropriate, right?) on Lydia with flames/fire bolt/fire rune and console commands.

-In most cases, dual-casting deals roughly 10% more damage than single-casting twice. It definitely deals more damage than single-casting twice, but it's hard to be exact with the percentage, since you can't hurt yourself with your own spells (including Fire Rune, which won't go off if you or your companions walk over it, and even won't damage you (but will damage your companions) if you set it off with something like Flames).
This is comparable to the Conjuration dual-casting bonus, though, where dual-cast Conjuration spells last exactly 10% more than twice the single-cast duration, as determined by the effect's description on the Active Effects page.

-In all cases examined, dual-casting costs exactly 40% (well, with some rounding to whole numbers) more mana than single-casting twice.

-As your Destruction skill goes up, Destruction spell costs go down. For example, increasing Destruction from 21 to 100 lowered spell costs to 65%-70% of their original value. This is true for spells both covered and not covered by your mana cost-reducing perks, e.g. Novice Destruction.

-Magicka regeneration stops while "holding" a pre-cast spell (obvious) and while channeling spells like Flames (maybe not so obvious)

-Flame Cloak is a bugged exception: it still has 280% of the single-cast mana cost, but according to the Active Effects page gains nothing (i.e. neither damage nor duration) from being dual-cast.

So let me see if I understand this correctly.

Casting 1x = 100% damage + 100% magicka cost
Casting 2x = 200% damage + 200% magicka cost
Dual Casting = 210% damage + 240% magicka cost

or is it

Dual Casting = 110% damage + 140% magicka cost

or is it something else entirely?

Casting 1x = 100% damage + 100% magicka cost
Casting 2x = 200% damage + 200% magicka cost
Dual Casting = 220% damage + 280% magicka cost

... so dual casting, compared to simply casting 2x, gives you (220% - 200%)/200% = 10% more damage for (280% - 200%)/200% = 40% more mana.

Well, that sounds kinda lame :S Why would Dual Casting (that requires a perk) be less effective than just casting 2x a spell?

You get ranged staggers with dual casting. It's one of the most OP mechanics in a one on one situation in the game.

You are paying the mana for the stagger. Or at least that's how I've viewed it while playing.

yeah i noticed this too and i wish i had not spent the perks in it sadly

edit: i focussed on restoration heals, no stagger bonus for me that way. just a bad perk.

Because Todd Howard has a sick sense of humor.

I believe it's for balance. To cast a spell twice would take, well, twice as long (I assume). Dual casting allows you to deal that damage now, rather than in a few seconds. The cost for dealing the extra damage now is increased magicka cost.

That's my theory anyway.

This

I almost regret getting this perk because sometimes it makes the game too easy, even though I'm playing on expert. It makes most dragon fights a joke.

serious balance issues in this game. but 10% more damage isn't too bad. for 1 perk

That's pretty stupid. It should be more efficient, not less.

this

It's about instant damage potential isn't it. Like over-clocking your pc, you get more performance but at the expense of more heat and potentially shorter life. So with the magic you do more damage per second but at more mana cost and so with the downside to run out sooner. Hopefully that extra 20% will be enough to take the critter down before they kill you.


I think it pans out ok in the long run, cos you don't want such an early perk to make you too badass.
Not to go off topic too much but there are a lot of people who are also comparing magic damage potential with weapons and saying destruction is too weak. I think they are missing one important point, most spells have a decent range so you can kill at a distance. A sword has about 6 ft of range. I will be honest I haven't seen any stats for maxing out bows vs destruction spell but I have a feeling bows will be weaker on DPS.

Which requires another perk. If you don't get that perk (granted everyone who goes into Destruction probably gets it) then you are paying extra mana for not much benefit.

But it's not really a balanced cost. 10% damage for 40% magicka. Also you can cast twice at the same time without actually dual casting and incur no penalties (2x spell for 2x cost, instead of 2.1x spell for 2.4x cost)

But what other perks have negative sides? This perk increases Damage by 10% for an increased Magicka cost by 40%

See above reply.

Dual casting gets you more damage, more quickly. It's not worth using over time compared to just casting twice, but if you want to finish off an enemy you know you can handle in one mana pool, dual casting will finish the job faster. And it looks awesome...

and again, for restoration this perk is a waisted point... for damaging spells i see the point with stagger but for healing??

I have a question which isn't strictly on-topic for this thread, but seems close enough to be a good place for it. Is it just my imagination, or is there a benefit from 'bursting' destruction spells for like 1 second at a time? Sort of a tap-tap-tap casting? I could swear I do damage faster to enemies when I tap-tap-tap than if I hold down continuously (I think this is especially true with Flames, because you get the 'bonus' damage for casting the spell at an enemy on fire, but if you cast continuously, you don't get the bonus, I think; but, it also seems true for sparks and frostbite too)?

I haven't playtested magic much, but I did notice that if you start one spell first then start the second you get different results than using both at the same time. You might want play test that to see if it is substantially different from regular dual casting.

So basically, only dual cast when needed~

That is all find and dandy, but you are getting small benefit for a large investment. What other perks have a negetive aspect to them? 10% damage for 40% magicka is kinda a lame tradeoff.

I have noticed this as well.

Maybe that's why the stagger perk is in the "Destruction" perks and not the "Restoration" perks? As far as I know, the perks in the destruction school only apply to destruction spells. I'm not sure why anyone even brought up "Stagger" in connection to Restoration spells?

I guess you're referring to the Restoration version of Dual Casting which is a seperate perk unto itself? The answer for why they would increase the magicka cost more than the benefit is, as other's have mentioned, being able to get a 10% bonus to magnitude-per-second is huge. People seem to be discounting the value of time, which I don't understand why they would. Casting a spell and having it do an extra 10% of the "normal" damage/healing (as opposed to the amount you would get by double-casting [that is, two handed casting without the perk) for an extra 40% magicka may be a fair trade off (OK, at the beginning of the game when your magicka pool is low, it svcks, but once you get a larger magicka pool, some potions of restore magicka and regen magicka, some good enchanted clothing/jewelry with magicka regen, and the "base cost" of spells goes down with increased skill level, then magicka becomes kind of "cheap").

You do have to realize that some of the "balance" in this game has to take into account other things like those magicka regen enchantments, and magicka restore potions. Gotta give people a reason to use/need more magicka from pots and enchants.

I knew from day one as a caster that the perk was horribly inefficient. At the point in which you can pick it up, you simply do not have the mana to support it, and against dragons or long fights you would have done much better had you not even bothered getting it. It's a horribly bad perk. I assumed it was something like +20% damage for 40% more mana, but it's not even that good apparently.

http://www.gamesas.com/index.php?/topic/1257568-does-the-dual-casting-perk-actually-do-anything/



False. You don't automatically get staggers from picking it up. You have to pick up Impact as well.

You guys are also kind of missing the point. You could "dual cast" without the perk before, but with the perk you end up having to resort to one hand casting if you want to remain efficient. You did more damage during long fights before the perk by casting simultaneous spells than with it. Single casting because of a bad perk design is still a bad design. Eventually you can get the cost of Destro spells so low that they are literally free, but you won't have that for the majority of the game, and especially not when you first get that perk. The stun from Impact is also grossly overrated. The only time it ever matters is against something that can kill you in 1-2 hits...which is only a named elite or boss.

You can stagger dragons? I can't on master.

Seem fair considering how much Impact has helped my player. I usually start all big battles with a few Impact Fireballs to stagger the enemy while I run to safety or get other spells up.

One more reason to keep pumping points into magicka..

Dual casting is a must have for illusionists - if a foe is too high level you're screwed, casting 2 spells won't make it any better. Having that extra 10% on top your other buffs can add up to 5 or 6 levels by end game