Quote Originally Posted by daman4567 View Post
If you only consider straight potency. Aoe rotation requires a lot of waiting for mp ticks if you are unlucky, or if you have just enough SS that you cast Fire III within one server tick. Once there gets to be around 8 or more enemies, thunder would definitely not be worth it, but if you find yourself waiting for MP ticks during aoe a lot, the breakpoint is probably a bit higher than 4-5 mobs.
If your Spell Speed is around 900, you won't be waiting on that MP tick, and a thundercloud means your 15 second cycle becomes 18 seconds. At 5 mobs, that's ~780 potency per 3 seconds. Using a thundercloud takes 3 seconds due to server MP tick, for only 710 potency. And that's assuming that the mob is alive for the full 24 seconds.