I returned a 2009 2.8GHz i7 27" iMac because of a very loud pitched "dog whistle" noise coming from the screen inverter. It was like a very high pitched electronic squeal. Has anybody had this experience on ANY 2010 revision iMacs (27" OR 21.5")?? I'm thinking about getting one for my work computer, and I'd like to know if they got this problem worked out yet. I did some research on the internet and there were countless reports of other people having this same problem with their loud, high-pitched "noisy screen" squeal issues. Thanks.