Its pretty loud. I bough one, used it for a day and am going to return it. It makes a high pitched whining sound and was too loud for me( which says something because i have 13 fans running in my computer).
2 hard drive coolers(with 3 fans each)
80mm front intake fan
80 mm rear exhaust fan
power supply fan
pci slot fan
heatsink fan
60mm fan mounted on top of heatsink
2coolPC fan and duct system