H100i High Pitch Noise from Fans

Hi all,



I got this high pitch noise comming from my new led SP120 connected from the Y-spliter of the H100i.



After some more testing i discover the following:



-This high pitch noise is coming from the motor of the fan, I stopped the fan with my finger (kids do not try this at home) and the noise is still there so it's not from the blades.



-Noise only occur when they are not runnin at full speed



-When the SP120 is connected to SYS_FAN on the motherboard, no noise.



-Switched back to the stock H100i 4 pins fan, tried low rpm and max rpm, no high pitch noise



-Connected my AF120 to the H100i, same noise



I did some googling most of the similar issue seems to be the fans or firmware, my version is 1.0.7 and in my case it does not look like it's the fans causing the problem.



Any advise is apperciated. Thanks in advance.