This is a common issue with the models, many say their screens have warped images, green lines, i got this iMac on ebay and a few months later i experienced the same issue plus freezing just from watching youtube videos, but you guys wont believe this one, and i asked on ifix it too and its too early for a answer yet,
A P.C. friend of mine suggested to connect his Samsung 21" VGA DVI monitor, i like any apple person assumed this would only put more stress on the imac, but it turned out to be the opposite, i have no idea still why the hell the iMac all the sudden works faster, smoother, i even had several youtube videos running, VLC and final cut x, no more green lines, no more warped images, no more freeze ups other then rendering of FCP x, but thats not all, the iMac's screen all the sudden looked pristine, and i get a very rock solid performance now, why is that, anyone know?
A P.C. friend of mine suggested to connect his Samsung 21" VGA DVI monitor, i like any apple person assumed this would only put more stress on the imac, but it turned out to be the opposite, i have no idea still why the hell the iMac all the sudden works faster, smoother, i even had several youtube videos running, VLC and final cut x, no more green lines, no more warped images, no more freeze ups other then rendering of FCP x, but thats not all, the iMac's screen all the sudden looked pristine, and i get a very rock solid performance now, why is that, anyone know?