You may want to try some stress tests/benchmarks. e.g. Firestrike's stability test and benchmarks.
See if that provokes the issue.
Then I'd second the suggestion to call PCS and see what they have to suggest. At least you know it's not just one game, although that's probably not good news I'm afraid.
One other thing you could try with your clean Windows install that you've done is to remove the drivers with DDU again and reinstall an older version of the drivers. Maybe from several months ago (they have driver versions going back about a year on the Nvidia site) https://www.nvidia.co.uk/Download/Find.aspx?lang=en-uk and see if it does anything.
Alright I went and did a clean install of older drivers.
I went with the 388 Drivers from the 23rd of October 2017
Here is what I ran:
1) Firestrike Benchmark test:
Demo video completed fine.
Right at the end of graphics test 1 the artifacts appeared again, screen froze just like on all other occurrences and then I restarted the pc by hand after a minute of staring at the frozen, artifact-filled screen.
I guess this makes it a hardware issue then ?
Additionally I can't even call PCS right now since they apparently are not there on weekends. Guess I'll just have to wait till monday.
Ok that means there's nothing I can do except wait till Monday then I guess.
Thanks for the help.