The silver control knob on the back of the Logisys Glacier power supply controls the speed of the two fans... Unfortunately the control knob was not very reliable; it only worked for about an hour. During that hour, I was able to adjust the speed of the fans (and the brightness of the fan LEDs). Shortly thereafter, I needed to leave the room so I turned the fans down to the middle speed. When I came back, the fans were off...



Link: BigBruin