From WoWWiki
Arcane Instability is a Mage talent that increases spell damage and critical strike chance. This affects all three spell schools the mage has. The spell damage bonus applies to the spell damage from gear and stats, where the critical strike chance is a flat percent increase. This is an all around good talent for increasing damage, as it scales well with gear upgrades.
This talent requires Presence of Mind and is a pre-requisite for Arcane Power.
| Rank | Spell damage increase | Crit chance increase
|
| 1 | 1% | 1%
|
| 2 | 2% | 2%
|
| 3 | 3% | 3%
|