Corsair Professional AX760i / AX860i PSU review: extremely efficient
 

With prices of £158 and £166 respectively, the Corsair AX760i and AX860i are more expensive than the power supplies from our recent round-up, but you do get high-quality PSUs for that price. Their efficiency is outstanding, they're extremely quiet and the voltages are super-stable.

http://uk.hardware.info/reviews/3640...mely-efficient