I received my new iMac 27" (i5 / 580 / SSD 512GB) two weeks ago. After the initial setup, I notice that the iMac was making an high pitch noise intermittently. Retuning the iMac, I get a new iMac 27" (i5 / 580 / SSD 1TB) today and it has same issue. Does anybody has a high pitch noise problem? I'm considering a second replacement order.