Hello. I've had my iMac 27 i3 for almost one year now and it allways did "normal" HDD noise when, for instance, saving or copying files. Today I've detected like an irregular buzz hum or vibration that is really annoying. It has nothing to do with regular HDD noise wich is acceptable, but this one gets on my nerves. I don't know if it's from the HDD or from another component but it just seems to hapen randomly (more if you're activelly using the computer). Hm... hm hm. Stops for some seconds. Hm hm... hm hm Any suggestion/help? My main problem is that I ordered the computer on the Internet and there's no close (I think closest is more than 300 Km away) apple store. Thanks. *EDIT* Sorry I have to say that after lots of tests I've discarded the sound coming from the iMac wich surprisingly has made the sound irritate me less. At least I know it's not from my iMac.