Tweaknews.net has posted a review on the Thermaltake Toughpower Q-Fan W0163RU 650Watt Modular Power Supply A quote from the article:

With four independent 12V rails providing stable power, it is a fine choice for an overclocked rig. The 140mm Qfan does it job as well with its nearly silent operation even when under heavy load. In fact, this is the quietest PSU I've worked with that wasn't fanless.

Thermaltake Toughpower Q-Fan W0163RU 650Watt Modular Power Supply Review