Oh dear. I have already been though this many times with my previous 15" 2012 rMBP - it had three logic boards in it before Apple replaced it with a new 15" machine - this one. On the original 15" the failure would create a black screen and the inability to recover. So it was pretty conclusive each time. My mid-2015 15" rMBP has the discreet Graphics card. About a month after I got it - it took its first wobble. And its been happening on an increasingly regular basis now - such that its happening two or three times per day. It behaves differently though. It usually happens on Safari actually. You will click to load a new link, nothing will happen, you get the spinning umbrella, and then screen goes black and it returns to the opening sing-in/lock screen. You sign in and then Safari recovers.....takes a minute or two. I could deal with this, occasionally. Now however it is exhibiting a new variant of this behaviour - instead of gong back to the start screen though, the screen is going totally black, fans come on to full speed, and keyboard lights remain on. Machine either then restarts itself, or more often, I need to manually power it down by holding the power button - and then re-start it. This is becoming a real pain as it often loses some work or pages in the process. Is this consistent with other 2015 rMBP Graphic Chip issues - or is it something completely different? I am not getting a fault log or Kernel panic report - like I was with the older 15 rMBP" machine? Thanks for any suggestions?