When I power up my pc or resume from sleep,one of my case fans is very noisy and runs at 200rpm only,after about 5minutes while the pc is still running,the fan slowly becomes more and more silent and reaches 1200rpm(its rated speed) and is fine after that,until the next time I start my pc or resume from shutdown...also if I only restart pc,it works fine.Is the fan failing? can someone tell me whats going on..I tried connecting it to the psu and on the mobo 3pin header,same issue.I have 4 other 120mm fans running at 1200rpm without any problems.Will a 7v mod on the fan fix the issue? also what happens if I connect a 7v and 12v fan on the same molex cable and then to psu?