In addition, an affordable 550 W SFX unit will be added to the company's SFX series, featuring only native cables in order to restrict production costs and allow for a lower retail price. The SX550 will feature 80 PLUS Gold efficiency and a single +12V rail, which can deliver up to 45 A of current.
http://www.tomshardware.com/news/silverstone-sfx-digital-psu-computex,29303.html