Let’s not mince words here.
The Chaotic Skyflare Diamond, affectionately known as the CSD, is the best metagem that you, as a mage, can get.
For raiding, it provides a massive DPS increase that no other metagem can even hope to match. In fact, the CSD is so powerful, that any helm that doesn’t have a metagem socket is automatically a terrible helm for mages.
It’s even a fantastic gem for PvP, due to it’s ability to negate the effect of resilience. In fact, the only other PvP gem that’s even half as good is the Tireless Skyflare Diamond. The other gems… crap. Crap, I say!
I am sure many, if not most of you know that the CSD is the best thing to happen to hats since Odd Job. But maybe you don’t know why.
I am here today, ladies and gents, to tell you why the CSD is the greatest thing to happen to mages since conjured sliced bread.
Obviously, it’s that extra 3% to critical strikes that’s important.
Warning: There be math ahead!
(For those of you who, uhm, might need a warning for such a thing. Maybe you suffer from mathilepsy or acute enmathilitis lethargica. Who am i to judge?)
Say you have a spell. This spell crits for 5000 damage. If you had the CSD, that same crit would be 5150 damage. Right there, the CSD just gave you 150 extra damage. No other metagem comes even close to that kind of DPS boost.
But hey, that was pretend. Let’s get to the real stuff.
The most important feature of the CSD is that it scales with extra crit modifiers. It works multiplicatively, rather than additively; this is why it’s so damn good.
For simplicity’s sake, let’s take a look at the Arcane tree. Specifically, the talent Spell Power.
Spell Power increases the critical strike damage bonus of your spells by 50%. As a mage, your crits normally hit for 150% of the damage they would normally deal.
Say you hit for 3000 damage with Arcane Blast. If that spell crits, the damage would therefore be:
3000*1.5 = 4500 damage.
With Spell Power, your crits would go up to 175%, so in this case:
3000*1.75 = 5250 damage.
Note: Remember that the 50% is specific to the critical strike damage bonus. In other words, the bonus 50% for criticals is multiplied by 50% (resulting in a further 25%), thus becoming 175% total.
Logically, the CSD would simply add on top of this. Your crits currently hit for 175% damage, so adding another 3% would change that to 178% damage, or in this specific case:
3000*1.78 = 5340 damage.
CSD doesn’t work that way. Nooo, that would be simple and really easy to understand. So you can understand why Blizzard isn’t a fan.
No, see, CSD works by taking your final crit damage, and then adding on the extra 3% to that number. Sticking with the same Arcane Blast example:
(3000*1.75)*1.03 = 5407 damage.
Arcane Blast crits, gaining the crit damage bonus of 75%, resulting in a crit of 5250. The CSD takes that number, and then multiplies it again for a total of 5407 damage. An extra 157 damage from a single gem.
Even better? The CSD actually performs the worst with Arcane mages, due to their relatively tiny boost to critical strike damage.
Let’s take a look at the frost tree, and the beauteous magic of Ice Shards. This little talent boosts the critical strike damage bonus of frost spells by 100%, for a total of 200% critical strikes (100% of 50% is 50%).
Once again, frostbolt hits for 3000 damage. Therefore, on a crit:
3000*2 = 6000 damage.
Throwing in the CSD, it takes that final damage of 6000 and amplifies that, giving us:
(3000*2)*1.03 = 6180 damage.
Let’s ramp up the crits a little more, shall we?
Anyone remember our good friend Ignite?
Let’s take Fireball. A Fireball based spec only has access to Burnout as a crit multiplier, which is (again) 50%. So let’s throw in the CSD:
(3000*1.75)*1.03 = 5407 damage.
What Ignite does is take the final crit damage, after the CSD is applied, and uses that damage to calculate it’s own damage. A Fireball crit, in total, would therefore be:
((3000*1.75)*1.03)*1.4 = 7570 damage.
To compare, if there was no CSD in the equation:
(3000*1.75)*1.4 = 7350 damage.
That’s a difference of 220 damage.
And to throw out the most extreme case, take a standard 0/53/18 Frostfire build.
Ice Shards and Burnout stack additively, meaning Frostfire Bolt gets a crit modifier of 225%. And then, of course, on top of that, Ignite starts doing it’s thing.
(3000*2.25)*1.4 =9450 damage.
The base crit is 6750, with Ignite pushing the total damage up much higher. With CSD:
((3000*2.25)*1.03)*1.4 = 9733.
That’s a boost of 283 damage, all because of one little metagem named CSD. There just isn’t any competition to that.
Resilience does two things. It reduces the chance that someone is critically struck, and reduces the damage they take from critical strikes.
Specifically, 1% resilience rating reduces the critical strike chance by 1%, and the damage taken from critical strikes by 2.2%.
Exactly counter to that, the CSD increases the damage of critical strikes by 3%.
In order to negate 3% of the damage from an incoming critical strike, a player would need to have 1.36 (repeating, of course) percent resilience, or 112 resilience rating.
In other words, just by equipping the CSD, you have immediately negated 112 resilience on your targets.
And there you have it.
Now you know they why of the CSD, and now we can put on our robes and wizard hats and revel in the awesome.