* Proc rate appears to be 10-12.5%
* Has no internal cooldown, can refresh itself but does not stack. Procs off both white and yellow attacks.
* Does debuff Raid Bosses.
* Does not stack with Thunderclap. Debuff replaces Thunderclap and is bigger than Thunderclap. Further Thunderclaps continue to do damage/threat as normal but does not further slow the target.
* For curious Frost Mages, enchant is affected by Arctic Winds 5% damage bonus, and Winter's Chill crit debuff. Not affected by spelldmg or Piercing Ice or Ice Shards.
* Replaces debuff from [Riftmaker].
The basic effects are:
Permanently enchant a weapon so your damaging spells and melee hits occasionally inflict an additional 150 Frost damage and reduce the target's melee, ranged, and casting speed by 15% for 4 sec. Requires a level 60 or higher item.
As an OT enchant, its not bad. It will give a dps boost from the frost damage. As well it will give an occasional boost to the effect of Thuderclap. Hyrion noted that both spell effect icons can show at the same time.