Kingwin LZP-550 Lazer Platinum 550 W
 

The Kingwin Lazer Platinum LZP-550 is based on Super Flower's platinum platform (Golden King 550W) and according to the manufacturer achieves over 92% efficiency. The power supply's fan will only spin beyond a certain temperature, so the PSU will emit no noise at low loads. In our review we find that this power supply is the best model available in its power range at this time.

http://www.techpowerup.com/reviews/Kingwin/LZP-550/