Hi, New member here, just upgraded today from a 2009 24" iMac to a brand new 2013 iMac. Specs are: 3.4 Intel Core i5, 1TB Fusion drive, GTX 780M, 8Gb RAM, came with 10.8.4 but i installed 10.9 This iMac is perfect, screen is as good as it can get, i am very happy with it. ( i really don't want to have to go through 3 of them before i get a keeper like i did 4 years ago with the 24") Problem is that for some reason it doesn't like my B&W MM-1 speakers. I have used the computer around 5 hours and have had 2 different issues: - I hear a screetching through the MM-1s and all sound stops, only way to get them back on is to turn them off and on, reselect them in system preferences/ sound/ output. All is good for a while. This happened twice. - Sound stops, everything freezes, no mouse, no keyboard, nothing. Only way to get things back on is to hold the power button on till it shuts down and reboot. Weird thing is the computer is still running, if i wait for a bit i can see the name of the next song appear in the top right corner, i just can't do anything! This happened 3 times. Of course the speakers never gave me a problem until this new iMac. Any ideas? Does it sound like a software issue? Hardware? Send it back? Keep it?