Your spell power is now equal to 65% of your attack power, and you no longer benefit from other sources of spell power.
Your instant spells and totems cost 75% less mana and your shock spells cost 90% less mana.
Your melee attacks have a 40% chance to immediately restore 5% of your mana.
Mental Quickness is a passive shaman ability learned at level 10 for those with the enhancement specialization. It increases spell power to 65% of attack power, reduces the cost of instant beneficial, damaging, totem, and shock spells, and grants a chance for melee attacks to restore a small amount of mana.
Patch 5.3.0 (21-May-2013): Mental Quickness now converts 65% of the Shaman's attack power to spell power, up from 55%.
Patch 5.2.0 (5-Mar-2013): Mental Quickness now lowers the cost of shocks by 90% (still lowers the cost of other "beneficial, instant, damaging and totem spells” by 75%).
Patch 4.3.0 (29-Nov-2011): Mental Quickness has been redesigned. Instead of granting the shaman spell power, Mental Quickness now causes Enhancement shaman spells to behave as though the shaman has spell power equal to 55% of attack power. Enhancement shaman spells no longer benefit from spell power from other sources.
Patch 4.1.0 (26-Apr-2011): Mental Quickness now reduces the mana cost of Spiritwalker's Grace.
Patch 3.0.8 (2009-01-20): Mental Quickness and Static Shock have switched positions in the talent tree.; Reduces the mana cost of instant cast Shaman spells by 2/4/6% and increases spell power by an amount equal to 10/20/30% of your attack power.