I have just come from the new Apple store in Hornsby, having returned the second iMac 27 inch computer with a hum/buzz/vibration noise complaint. APPLE THIS IS NOT A MYTH AND NOT ACCEPTABLE! The story goes like this... I bought a 3.4 Ghz, quad core 27 inch iMac with a 1TB Seagate HDD and 8GB of RAM, and the 1GB video card a few months ago from the Apple store in Castle Hill, Sydney NSW. Took the machine home, set it up, and was extremely happy with it. Upgraded to Lion, had no issues with performance or ambient noise etc... it was whisper quiet. I would leave the machine running all the time, letting it simply sleep when inactive, and it never made a sound other than the optical drive or maybe occasionally the drive heads when reading or writing data. It was dead silent! I receieved an email from Apple stating that in some circumstances the Seagate drive could fail, and for me to contact a store to make an appointment to have the drive replaced as part of a product recall. I thought 'I'll do the right thing' and made an appointment with Castle Hill Apple store to see a 'Genius'. Here comes my first gripe! I am an IT professional myslef (a CIO with a technical background) I should add, at this point. When I made the appointment I was unable to ascertain the status of stock for the replacement hard drives or how long the replacement would take. I get to Castle Hill and I am advised that the drives are not in stock and it could take a few days to get this completed. I don't want to be without my new computer for that long!? So I take it home and rethink how I should approach this. Hornsby Apple store opens! I live in Hornsby so that suits me! On talking to a representative at the Hornsby store just this Friday passed I am advised that they do have the 1TB replacement drives in stock so make an appointment quick smart! So I do. It goes downhill from here... On Sunday just passed I drop my iMac with a Seagate 1TB HDD in for hard drive replacement. As my data needed to be transferred from one drive to the other, I was told it would take overnight. No problem I thought. All good. I pick up the iMac the next day, with the Seagate drive replaced with a Western Digital one, and take it home. Set it up and turn it on. Suddenly my iMac is no longer 'whisper quiet'. From the point the system status chord sounds there is a humming or buzzing 'droan' that resonates through the desk and can be heard even over my television, fridge and fish tank! Sitting in front of the iMac for more than 10 minutes results in discomfort from the sound. It didn't make this noise before!? My assumption was that the new drive was either faulty or incorrectly installed. Dissapointed, and informed by reading countless blogs and forums on others returning multiple iMacs with the same complaint, I box back up my iMac (which I had previously been VERY happy with - previous to it being a buzzing machine that was) and the next morning (Tuesday) return it to the Hornsby store. At this point I must note that the staff (Manager Kate and Technician or 'Genius' James) have been outstanding in terms of customer support. I cannot fault the staff at this point, just the product. Tuesday morning the folks at the Apple store advise that they can either try to repair my now noisy iMac, or replace it. I figure, well I'll replace it then. So James sets about that day transferring all my data again, moving my 8GB of Ram from the machine to a new machine. The new machine has in it of course, a Western Digital drive (not that I am attributing the hum/buzz/vibration to the WD drive, but it is an odd coincidence don't you think?). I pick that machine up Tuesday afternoon, thanking everyone for all their wonderful help, and knocking on wood that this new machine is as faultless as my first one was prior to the drive replacement. Guess what!? It wasn't!!! So I return the second machine this morning. You guessed it... I am now irate. The 'Genius' told me he could not recreate the issue... OF COURSE! GENIUS! You have music in the background and it's a noisy store! I wish I had never let anyone touch my iMac in the first place. As I've said I've read countless forums on this issue - it DOES EXIST! If I pick up the machine when running, the buzz vanishes. You can FEEL the vibration through the stand. If you lean the machine forwards onto the front ledge of the stand the sound goes. It is something to do with a moving component that is creating a vibration and in quiet environments the noise actually becomes irritant. I left my iMac running overnight and from my bedroom, I could hear the droan. The desk is a wooden desk, on tiled floor - but I must impress, MY FIRST iMac DID NOT MAKE THIS DROAN! Anyone wish to comment? Apple maybe!? The iMac is in the shop for further diagnostics.