Reduces the mana cost of all spells by X% and reduces the threat caused by your Frost spells by Y%.
Frost Channeling is a mage talent that reduces the mage's spells mana cost by 5% per rank and Frost spells' threat caused by 3-4% per rank, up to 10% mana reduction and 10% threat reduction at max rank 3. This talent is primarily taken by PvE raiding frost mages. The mana reduction helps with long boss fights, allowing the mage to favor spell power gear, sacrificing overall mana. The threat reduction allows the mage to safely do more damage.
Similar threat reduction talents include Burning Soul which reduces threat from Fire spells by 10% at max rank, and Arcane Subtlety, which reduces threat from Arcane spells by 40% at max rank. Other direct mana reduction talents include Precision which reduces the mana cost of Frost and Fire spells by 3% at max rank. Master of Elements effectively reduces the mana cost of Fire spells, by refunding mana on each crit.