Answer to: If fan in noisy, does it need replacement?POSSIBLE SOLUTION: I have a MacPro 3,1 (Mfg Sept 2008) which I have used from 18 to 20 hours a day since it was new. A month ago it started having noisy intake fan issues (the dual fans at the front of the computer). At first I thought it was a harddrive issue, but after replacing all my harddrives with Intel Sata 3 SSDs (Speed Demon 520s, which make NO NOISE at all) I realized it was Fan Noise (sounded like they were out of balance during a cold boot). Well, to make a long story short, the problem appears to have been a nearly dead CR2032 battery. At least the problem has not reoccurred or recurred again since replacing the 3 1/2 year old lithiums. It is at least worth a try if your battery is several years old. Update: Fan Noisy and sounds wobbly prior to the boot "Chime" (Bong) then it smoothes out. Discovered that my APC UPS backup power supply was defective and not generating smooth sine wave and/OR it was distorting the sine wave AC being fed to the computer.