yeah i dont get it, if i selcect fire in one hand and then in the other i can dual cast, but i dont have the perk, does the perk just make it more powerfull? can i dual cast any spells straight away?

You can cast from each hand and get double the effect. You are not actually dual casting but casting with each hand seperately.

The perk gives 20% more damage but costs more magicka. Plus the impact perk only works with dual casting

If you have the perk you can have the spell in both hands and combine it into a more powerful version. 2.3 times the power and 2.5 times the cost, if memory serves

Edit: Nope, 2.2 times the power, 2.8 the cost. Seriously?

cuz u should trust bethesda... :3

and also cuz it increases the damage done and the mana cost, and applies to all destro spells except for (in my experience) the rune spells, which increases your damage done and lets you 4 shot dragons with a dual-casted ice storm.

thebit that confuses me is that the perk says dual casting, and really you are dual casting, if your holding a spell in both hands that in itself is dual casting, if i understand you guys really the perk just means you can hold it down it it turns more powerfull, like charges up rather than just firing normal

Try "dual-casting" a Fireball your way. All you do is cast two separate fireballs.

With the dual-casting perk, you cast one super-charged fireball.

You are casting the single spell twice, one in each hand, with seperate "single cast" visual effects coming from each hand (two seperate effects). Dual casting combines the spell from each hand into one more powerful spell with one visual effect from both hands combined, not two seperate as you are doing it. But it costs more magicka and does more damage than casting two spells.

And again, the Impact perk only works with Dual Casting and not with casting single spells from both hands.

Morgan - go out somewhere quiet, and pick a rock or tree for your target. Then try to hit both your left and right mouse buttons (or console equivalent) at exactly the same time. Instead of your two hands separately clenching and ready to cast the fireball (or whatever you use), you should see BOTH your hands come together to make a larger and more powerful single fireball. THAT is dual casting, and it is well worth it. If your hand stay apart, you've missed it.