Dual boxing mages: Lvling fire or frost?

[fpanko]

It's really up to you, they will all work just fine.

I did 2 frost.
Then 1 frost 1 fire.
Now I do 2 fire.
Mobs die so fast, they almost never touch me. I never need cc beyond the occasional sheep(s).
It's also pretty mana efficient, so I don't have have to sit and drink very often. Just kill a mob, run to the next one and repeat.

[TheBigBB]

I like deep arc/fire because you get the most awesome burst DPS ever. POM-AP-Pyro is insane even with one mage. Also, arcane missiles will keep hitting opponents who run out of LOS as long as they were in LOS on the initial cast.

[Sanctume]

If you have 2 3-minute mages, then you technically have a 1.5 minute mage.
If you 3-box, then you have a minute mage.
4-box would be a 40 second mage.