Vivalabambam posted a comment in the 3.3 gear post which asked when it might make sense to consider using the [Ember Skyflare Diamond] instead of the [Insightful Earthsiege Diamond].
Holy paladins, by and large, are taught to use the IED without question. The dogmatic justification for this is that it will take an outrageous amount of Intellect for 2% to approach 21, that the mana from the IED is useful, and that the spell power from the ESD is useless.
Viv’s — I can call you Viv, right? I’m not sure what else to do with such a fantastic name — question is based on the clever observation that the metas were designed back in early wrath before gear scaling was inflated by the introduction of heroic gear tiers. As our gear scales into the stratosphere in ICC it makes sense to re-evaluate gems which scale with that inflated gear.
It’s an interesting question. Let’s take a look.
2% vs. 21
In deconstructing the comparison, we first can look at the Intellect bonuses of the two gems. On the surface it’s a trivial question. At what level of Intellect will a 2% bonus equal 21?
X * .02 = 21
X = 21 / .02
X = 1050
So you’d have more Intellect by wearing the IED if you have more than 1050 Intellect, right? Heavens, no. We’d all have switched to the ESD long ago if this were the case.
The first complication is the activation cost of the meta effect of each gem. If we’re stacking Intellect we can activate the IED with one [Nightmare Tear] and put [Brilliant King's Amber] in all the rest of our sockets. If we’re activating the ESD we must have three gems with red components. Activating the ESD requires socking two more gems with red components at a cost of 20 Int.
Raid buffs are the second complication. The 2% bonus from the ESD stacks Gift of the Wild and Arcane Brilliance. Blessing of Kings stacks with the bonus of both gems and so can be ignored. And yes, let’s keep it simple and assume people aren’t using [Elixir of Mighty Thoughts] — though I have been known to in some fights!
((X + 52 + 60) *.02) = 21 + (2 * 10)
X = (41 / .02) - 112
X = 1938
At 1938 Int from gear and talents the two gems will give the same amount of int when counting socketing costs and raid buffs. If you have more base Int than this the 2% of ESD will give more Int.
If you’re already wearing the IED, and have gemmed with a tear and all brilliant, that’ll be 1979 unbuffed in the character sheet and 2300 in the character sheet with full raid buffs.
If you’ve gemmed differently the cut-off point might be lower because you may already have red gems and have already been paying the activation cost of the ESD.
2% vs. MP5
If the gems only granted either 2% or 21 Int then it would be painfully obvious when to make the switch. But the ESD gives spell power and the IED has a chance to restore mana. It’s the IED’s proc, oh so cleverly named Mana Restore, that has everyone so excited. It has a 5% chance of restoring 600 mana with a 15 second internal cooldown. Let’s examine it in detail first.
The 5% proc chance means that the duration between procs varies wildly. Here are the seconds between procs that I saw on a 10m Marrowgar kill: 88, 35, 16, 47. Here are the total amounts of mana it gave in regular 10m ICC kills:
Marrowgar: 3000 mana / 207s = 70 MP5
Deathwhisper: 1800 mana / 214s = 40 MP5
Saurfang: 1800 mana / 247s = 35 MP5
Festergut: 1200 mana / 207s = 25 MP5
Rotface: 2400 mana / 244s = 25 MP5
So the IED proc gives us an unpredictable mana source. What else does that do for us? Absolutely nothing. It only returns mana.
The ESD’s 2% meta effect scales with our gear. As we get upgrades we get more Int than we would otherwise. For every 50 Int from upgrades we get 1.1 (with kings) additional Int. That, in turn, gives us more mana, spell power, and crit chance.
It should be possible, with a theoretical fight, to construct a sufficiently complicated model to compare the 2% Int benefit to the IED proc as Int scales with upgrades. The more mana we get from Int from the ESD the more mana we’ll get back from Divine Plea, Replenishment, and Seal of Wisdom. The more crit chance we have, the more mana we get back from Illumination. At some point the scaling regen from the ESD would truly overcome the static regen from IED. It would take an enormous amount of Int for that to be the case.
That sounds really complicated. I think there’s a much simpler way of looking at it: If you don’t have mana problems then IED’s mana restoration proc is worthless.
There’s an obvious test. Did you worry about having to use DP or did you ever drop below the amount of mana IED restores in a fight? Given our giant mana pools, and its unpredictable total returns, that’s a pretty low bar. When’s the last time you were at 3% mana in a fight? 8%? When’s the last time you really didn’t have some down time in a fight for a well timed DP?
If the mana proc is worthless then all the benefits from ESD’s scaling int, no matter how small, are better than nothing.
Should you? You tell me!
In the end, whether you’re interested in the ESD once it gives more Int comes down to how you’re comfortable playing. If you feel like you’re always chewing through mana and are having to worry about it then you might not like the ESD. If it feels like you haven’t worried about mana in months then you might be interested in toying with the tiny, but scaling, bonuses that the ESD gives as we get upgrades in ICC.
If you’re not sure, give it a shot. A few weeks ago I hit the transition point after a handful of ICC upgrades and made the switch. So far, so good.
(This was edited from the initial post. Having spent most of the post typing “2%”, I initially mistyped the IED’s proc as 2%, not the current best guess of 5%.)
