The Asus Radeon HD 4870 Matrix features two fans without a restrictive shroud, giving the heatsink more room to "breathe", and providing direct airflow to the GPU and board components. By sharing the cooling work between two fans, it should be a quieter, cooler card. We pit the Asus Matrix against ATI's reference design.
http://www.silentpcreview.com/asus-hd4870-matrix