Optical drive fan speed - and noise

Question

I have a new 27" i7 3.4Ghz iMac and I'm extremely pleased with it's functionality, performance and good looks; however, a consistent and irritating "chugging" noise has just started to be heard ...or perhaps it's that I've just become aware of it. Anyway, having trawled the communities here and run iStat Pro it seems the optical drive fan is running 10% faster than default at about 1150RPM although the drive is not being used and the temp is low at 30 degrees.
Might this speed be the cause of the noise and why would it be over-speed anyway if the optical drive is not being used? And can I re-set it back to default without stuffing up the iMac??
Other data seems quite normal at:
CPU          939 RPM          32 degrees
HD          1101 RPM           29 / 35 degrees
Ambient                            16 degrees

Answer 1

Hello
at first check that you have no disk left in the drive.
According to Apple Support, reset SMC if the drive or the fan behavior seems not normal.
How to --> http://support.apple.com/kb/ht3964
If the drive produce an unusual series of noises after startup or system wake up from sleep, you may reset the optical drive as described below.
Insert a CD or DVD almost all the way into the drive. (until the drive want to start pulling in the disk)
On this point remove the disc.
Insert the disc fully into the optical disc drive.
Ceers - Lupunus