Hello, I was recently challenged to fix this laptop and from the limited amount that I have read online, this appears to be a common issue with this gpu. I could be wrong, but this sounds like an overheating issue. It appeared to be the case with this macbook that I just "fixed" anyway. What I did: Completely took apart the macbook pro, removed the old thermal compound on the cpu/intel gpu and nvidia gpu. Applied heat with a utility lighter for 10 minutes each on the cpu/gpu combo and nvidia gpu. Reapplied thermal compound Put together MBP Applied thermal pads underneath the ram modules on the logic board. I've had the MBP on for 9 hours straight so far with no issues. I have tried YouTube, DVD Playback, xCode, and basically anything that comes with Yosemite stock. I am about to download steam and try to push it with games, but I am fairly optimistic that this shouldn't be a problem. My friend told me that it wouldn't even last an hour before shutting down on him. In fact, I am starting this thread right from this very macbook. Here is how the thermal pads look applied to the logic board: Anything else I should test that I might possibly be missing? This is a pretty nice machine...considering the fact that I got it for free. ---------- Also, I apologize if this is the wrong section for this.