It's not constant. Does it every 20 seconds or so after the hard drive has been active. I think it stops if the hard drive hasn't been called to action or left alone. It's a quiet noise not noticeable if there's background noise. In a completely silent room, it's consistent enough to notice. Wondering if y'all can check or have noticed this b4 or if it's unique to my Seagate 120GB drive that came with my 3 day old 17 incher. Computer is performing fine.