Artifact Lines and "Snow" Nvidia

Hello,

I was playing with an Nvidia 980 Ti card. It worked well, and could play at maximum settings but after a few hours it'd start to show white artifact dotted lines on edges and "snow" (little white flashing spots). I monitored the temperature and it wasn't overheating. I thus assumed the card was going bad.

Now I have an Nvidia GTX1080 and the same exact scenario is happening again. I'll play for hours and the lines and snow arrive. The temperature in my case is fine. I don't play other games so cannot check if this is happening elsewhere. If I exit the game and come back in, the behavior stops.

If anyone has an ideas or suggestions they'd be much appreciated. I can also send any addl. info. My PC is using a Skylake "K" processor, 32 GB RAM, SSD drive, 1gb network to Verizon FIOS fibre. Windows 10 latest updates, latest Nvidia drivers. Happens if I use DX9 or 11. I've filled it with fans (side intake, top outtake, back outtake, front intake) and really don't think it is temperature related but who knows :-(


UPDATE:

I ran two passes of memtest against the system thinking it may be bad RAM, but that all came back clean. I then checked temperatures. Running at Maximum I tend to hover at 63 C, on standard, 50 C. Uncertain if that helps; will keep looking.

UPDATE II:

That was 63 C standing in an empty room idle in the game. I imagine it'd go quite higher when actually doing something. If that's the case, this very well could be an overheating issue after all. Honestly, I'm hoping so, because that I can fix!