Started having this issue with my GTX1080 after recent Windows Updates/Driver Update, not sure with which specific one.
- Changed cables.
- Changed GPU. (I had a spare for testing.)
- Normally use stock clocks, tried undervolting.
- Changed displays.
- Reinstalled affected games.
- Completely cleaned out the drivers and reinstalled.
In the end, this isn't hardware instability. This appears to be related to the driver or Windows. Turning off GPU Scheduling and/or using the Debug option under Nvidia seems to have bypassed the issue, but it isn't a solution. The solution would be for the vendors to correct the new issue.
If you're asking yourself "Why am I being told to undervolt/underclock?" and the reason this might help some users is that it'll simply make your card slower and less likely to encounter the problem. It isn't a solution, it's just a way to avoid the problem.
In the end, your card isn't unstable and there's been plenty of feedback here expressing plenty of examples against that.