Stefan Mileschin

When a power supply becomes sufficiently efficient, it loses less energy from the input as heat. Given the right conditions, a very efficient and low rated power supply can be built without a fan, giving a quieter experience. The limit is always a balancing act between efficiency and seeing how highly rated the PSU can be – there is a certain segment of the market that will always prefer the quiet systems where possible. Up until this point, the peak rating I have used for a fanless PSU was 500W, from the Rosewill Silentnight range that were 80 PLUS Platinum rated. Even though Titanium rating has become a thing which might help push the limits even further in the interim, more fanless Platinum models are coming to market. SilverStone showcased a 520W Nightjar model and Enermax showed off a prototype 550W digital fanless version.

http://www.anandtech.com/show/8166/c...ne-and-enermax