It looks like you hit the nail on the head, but to be sure, I would update your video driver.
I have seen this pattern before, so I'd bet you have a GPU that is surface-mounted, and may use silver solder. It is really common on systems that have one heat-pipe connecting the GPU and CPU heat-sinks. You can have this re-worked, but it would not be cheap.
I am not recommending you do this, but I fixed one before by heating the GPU. There are all kinds of videos on YouTube about it. I surrounded the GPU with Aluminum Tape - the kind used to seal furnace ducts (NOT Duck Tape) to create a heat shield. Then, I used a pencil-torch to heat the GPU (moving it constantly). If you try something like that, you should look at the right way (GPU re-work using a IR soldering station), look at all the crazy stuff people do on YouTube, and make an informed decision. I will say that if you are not prepared to buy a new motherboard, or have a new GPU put on, don't do it because it would be really easy to ruin the GPU. I decided to try it because I was looking at $100 for re-work, $120 for a new motherboard, or $0 to give it a shot.
Surface-mount GPUs have flat contacts, but so does the motherboard. The GPU is placed under a template that holds balls of solder on the pins, while it passes through a balling oven. When it cools, the template is removed to reveal "pins" of solder. Next, it is mated to the motherboard with flux, and heated with an IR heat source.
When a system cannot cool properly and the system BIOS is set to shutdown too late, the solder melts and no longer makes a good connection. Often a dirty fan and/or heat-sink is to blame, but many times people will actually use their notebooks on their lap, a bed, a pillow or some other soft surface that blocks the vents! The computer industry started calling them "notebooks" so people would not put their "laptop"... on their lap.
Let us know what you do.
Good Luck