Originally Posted by rplat
Have the causes been isolated and identified on these unacceptable and abnormal noises?
I only know that Apple is offering to replace the HD or the whole iMac to people with this noise problem.
Here are some reports about the problems: http://www.listenupsteve.com/fixtheimac/?page=6
As regards my new 27" iMac, I got 1 dead pixel (but I find this acceptable), 12 iSight dead pixels, a yellow cast on the bottom right of the screen (very noticeable on a white background, but luckily I'm not a graphic pro) and the screen is noisy (a high pitch sound coming from the lcd panel, but it is presumably from the internal power adapter) when dimmed or when put to a stop (the screen is noisy for me only when the gpu temp is > 50°C, ie the majority of the time). I won't return it for now (unless it starts to flicker) because I heard that the chances that the replacement has the same or worse problems is not that low, so I'll wait as soon as all the problems are apparently fixed before sending mine for a repair. I'm reading that Apple is taking care of all the problems, even sending refunds to people who ask them, so kudos to them for that.
Other than that (which may be unacceptable for many), this is the best Mac I have ever owned. It has the speed I've always dreamed of when using OSX, and it looks simply stunning.