If you are 80 level arcane mage with 5.6K+ Gearscore and you are using 4xAB+AM rotation then you are doing it WRONG. My average on Heroic Training Dummy (83 level, Skull):
DPS for 30 sec is 14,731 (Total Damage: 441,936)
DPS for 60 sec is 11,979 (Total Damage: 718,766)
So called "burn phase" (casting "Arcane Blasts" only, no Evocation) lasts for 85.39 seconds.
I've yet to meet a mage in my realm who can beat that. I am easily ending as TOP 1 on DPS charts in raids with members who all have better GearScore (5.8K+).
Mage must convert mana to damage. If mage ends fight with 100% mana bar then mage is not using his full capacity. A lot of mages with high gear score play it wrong in Cataclysm by using old "4 x [Arcane Blast] + [Arcane Missiles]" rotation. Problem is that players are not realizing that high level (gear score) mages can use just [Arcane Blast] in long fights as long as their Haste is limited to certain amount. Slow [Arcane Blasts] (4 stack) can do much more damage than fast but old 4xAB+AM rotation. Assumption that Haste is always better than Crit is wrong. Haste is good in very short fights but gives you completely NOTHING in very long mana burn fights. Haste just depletes your mana faster while Crit offers more DPS per mana.
This is my rotation:
1. Hold [ALT] key and press [1] 4 times to get 4 stacks of Arcane Blast (+63% DPS).
2. Use [Spellsteal] (optional)
3. Press [Mirror Image] macro button.
4. Release [ALT] key and cast with [1] key - this will use all trinkets and buffs when you are at max DPS
5. Use Evocate when mana depleted (after ~1 min 20 sec).
6. Continue with Arcane Blasts (key [1]) and consider Arcane Missiles only when low on mana again.
All macros (attached to keys [1], [2]) are on:
WoW Arcane Mage - Resources