The reason for that is the way you're doing WoTLK Gold, which is enormously, which means you're putting enormous gaps to your game which will result in the result of a DPS reduction overall.

So you just always are queuing up the following Arcane Blast and then you can use the missile blast once that following Arcane Blast finishes. The final thing to note is that remember, it's an Arcane Mage, and you want to end the fight with no mana.

So, if the fight is looking like it's coming to an end. still have plenty of mana remaining. You can begin casting Arcane Blast WOW WoTLK Classic Gold chain using it to eliminate the remainder the mana.