I have a brand new maxed out 2015 retina iMac, I'm running 32gb of Crucial Ram with 1tb SSD and M395x graphics. Today I experienced an off problem today that concerns me. Machine is about 1 week old. I was working in Photoshop and had quite a few apps open, but both my screens froze (iMac and dell u3011) and my mouse became unresponsive. I was not doing anything overly intense at the time. I could still hear sound. I then saw some very bright twinkling artifacts on my iMac screen, about 5 inches long and an in inch high. Could be a graphics issue? My screen then blacked out and I saw the spinning shut down icon. Any ideas what's happening or if this is a common issue for others? Thanks!