Managing the Shatter Cap and Stat Priorities

Before we cover stat priorities, gearing, and various stat customization methods; we need to discuss the central aspect of PvE Frost that a Mage will have to constantly manage and work around through the various means available to them.

The Shatter Cap!
The Tier 1 Frost Talent "Shatter" triples the Mages critical strike rate against any "Frozen" target.  In a raid setting, where all bosses and most larger trash mobs can not be literally frozen, this effectively means that only spells that consume Fingers of Frost charges are affected by the Shatter Cap.  These spells include Deep Freeze, Frostfire Bolt (with Brain Freeze+Fingers of Frost), and Icelance.

The "Shatter Cap" is defined as the minimum critical strike rate necessary for all spells cast on "Frozen" targets to be 100% guaranteed critical strikes

This rate is 33.33%....repeating of course.

Gearing up for PvE Frost can be very tough. At effective critical strike rates below 33.33%, Frost will lose a significant amount of DPS because the "Shatter Cap" has not been fulfilled. Spells benefiting from the 100% Shatter Cap crit rate account for anywhere from 55%-60% of a Frost Mages total PvE damage output.  Fortunately, it is not necessary or desirable to reach the 33.33% critical strike rate through gear, enchants, reforging, or glyphs alone!

Raid Buffs, and Raid Debuffs are included when calculating your effective critical strike rate. These include:

+5% Critical Strike Chance (Feral Druid, Fury Warrior, Subtlety Rogue, Elemental Shaman, Hunter Pets[Wolf/Devilsaur]
+5% All Stats (Paladins[BoK], Druids[MotW], Hunter Pet[Shale Spider])
+3% Critical Strike Chance (Arcane Mages[Focus Magic])
+300 Intellect(.46% Critical Strike Chance [Flask of the Draconic Mind])

+5% Chance to be Critically Struck by Spells (Fire Mage[Critical Mass], Warlocks[Shadow and Flame])

To calculate the necessary critical strike chance from gear, enchants, gems, reforging, glyphs and armor spell choice that should be visible on your character sheet with only your armor spell active; use the following formula:
Self Buffed Shatter Cap Formula

Managing the Shatter Cap
Either through pure genius or coincidental luck, Blizzard has given PvE Frost Mages a degree of flexibility when it comes to Pre and Post Shatter Cap glyphs and Armor Spell choices. Remember that third Prime Glyph Spot discussed in the talent section? Here's where it becomes relevant!

Lets use a hypothetical scenario to explain...ok, it's not a hypothetical; it's what I deal with on any given raid night. =P

We have a PvE Frost Mage...lets call him...Critrocket.  Critrocket typically raids with a Feral Druid, Paladin, and a Warlock. This means he has +10.4% critical strike chance provided via buffs/debuffs in his raid.  His gear is customized so that he is at, or slightly under the Shatter Cap of 33.33%, with raid buffs/debuffs taken into account while running Mage Armor + Glyph of Frostbolt (so that he can be incredibly lazy and never have to manage his mana).

Mr. Warlock...or as Critrocket likes to call him, "Shadow and Flame Bot", is drunk in a gutter somewhere or his hard drive has taken a dump for tonight's raid. Critrocket's effective critical strike chance has now dropped by 5%, putting him 5% under the Shatter Cap because Shadow and Flame Bot isn't coming. All is not lost however...since Critrocket always carries glyph dust with him, he simply switches Glyph of Frostbolt (+5% crit on Frostbolt) with Glyph of Molten Armor (+5% crit on all spells while active).

Instead of running Mage Armor and Glyph of Frostbolt, he's now running Molten Armor and Glyph of Molten Armor and everytime he has to Evocate or Armor Dance he screams "FFFFF UUUUUU POLLO!!"...oh...sorry what were we talking about? Oh glyphs. Right.
Glyph and Armor Spell Guide

*There has been some debate as to whether using Molten Armor instead of Mage Armor at or past the Shatter Cap is an increase in DPS.  The trade off is essentially:

Unglyphed Molten Armor while Shatter Capped:
+3% critical strike on Frostbolt and Frostfire Orb (All other spells already Shatter Capped)

Mage Armor while Shatter Capped (in comparison to Molten Armor):
-6 or 12 seconds of additional DPS time(assuming one/two evocations)
-Rarely have to worry about mana
-Increased Magic Resistance

At a glance, the difference seems small enough to come down to personal preference. Neither choice can be considered "wrong" at this point.

Stat Priorities
It's important to note that while the Shatter Cap is very important for PvE Frost, it is only one piece of the puzzle.  Maintaining or approaching closer to the Shatter Cap should not be attempted at the expense of more desirable stats or equipping blatantly inferior gear! For Frost, stat priorities are as follows, in order of importance:

Pre and Post Shatter Cap Stat Priorities

Special Considerations: Intellect Proc Effects on The Shatter Cap and Stat Priorities
It is important to note that procs which grant Intellect also grant a temporary increase in critical strike chance! The combination of increased spell power and critical strike chance during these procs can push a given character up to, or over the Shatter Cap.  This can result in an overall shift from Pre-Shatter Cap stat priority to Post-Shatter Cap stat priority, even if a player is not technically Shatter Capped with no procs active!  For players with these trinkets/tinkers/enchants already at or over the cap with no active procs, this can result in a significant loss of potential DPS. Intellect procs can also push a player into a new Glyph + Armor combination even though their listed critical chance doesn't match up.

The math responsible for this is beyond the scope of what I will cover here, but I'm nearly certain that SimC models this behavior correctly.  Rawr may as well.  If this scenario applies to you, play around with them and let us know what you find out!

Commonly used items/enchants/tinkers that grant temporary Intellect buffs include:
Darkmoon Card: Volcano
Lightweave Embroidery
Power Torrent
Synapse Springs
Rune of Zeth

Next: Glossary, Mechanics, and DPS Cycles

-Critrocket [US - Malfurion]