Do I drop second rune of power during arcane power or do I hold it until arcane power is over?

[cryophobia]

Hi guys quick arcane mage question here-

When i am in burn phase I usually build 4 charges, mark of aluneth, arcane power, barrage, charged up, and then continue as normal. Am I supposed to drop another rune of power during arcane power even if there is only between 3 to 8 seconds of arcane power duration left? I usually wait to arcane power finished, drop second rune, dump the rest of my mana and then evocate.

What is the proper way to rune of power at a high level as arcane mage?

[magictricks]

If lust is running i usually drop the 2nd rune, if not then i dont.

[Eshelon]

Just assume AB does 100 dmg base, 'AB(100)', and thus it does 140 with RoP, AB(140). Now assume that casting RoP causes you to cast 1 less AB (it's possible that it causes you to cast 0 less but only if your haste is in a certain range... anyway, just assume you cast 1 less since that's going to be what happens most of the time. So now just count it out. How many X AB(140) hits, do you need to do more damage than X+1 AB(100) hits? The answer is 3. 3 AB(140) = 420dmg, where 4 AB(100) = 400 damage. So the answer depends on how many AB you will cast after the RoP goes down. If you can cast 3 or more AB after the 2nd RoP goes down, you're going to want to put down the RoP, which is why Magictricks always does it during lust; haste is so high that usually you can get 4 or Possibly even 5 AB after 2nd RoP, depending how many stacks of Aegwynn's Imperative you have from relics / NLC. If your AP lasts 14 - 15 sec, you can easily get 3+ AB. This is one of the reasons why Aegwynn's Imperative is the BEST artifact trait you can get.

The answer is the same in AOE situations with AE. If you can get 3 more AE casts before AP wears off, you're going to be ahead. This means for AOE it's almost always going to be better to use the 2nd RoP because the base GCD on AE is much lower than the base cast time of AB.