Originally Posted by jcleary47
I have two AF120's mounted horizontally on the top of the case, one attached to the Corsair water cooler for the CPU. It seems like if I don't run them on the highest speed, they make a noise. They don't make a ton of noise, but I'm wondering if they don't like being underpowered by the fan controller to run at a slower speed. I don't know.
I've heard that noise from many of the Corsair Air Series fans when under-volted by a fan controller. The fans are rated for best performance at 7-12v. I haven't had any problems with running my AF140 at 7v using the step-down voltage adapter that was provided by the manufacturer, but I avoided using a fan controller with it because of the noises they tend to make below 7v.
That said though, AF120's are a case fan and are terrible for use with a radiator in a water cooler. The AF120 fans have very low Static Pressure ratings, and without a high static pressure rating you get very poor airflow through a radiator because of the resistance to airflow the radiator creates. The Corsair SP120's are much better suited for use with a radiator because they have a higher static pressure rating.
If you really want a good radiator fan though, Gentle Typhoons are the way to go. Providing you can find them in stock any where.