Here I have a GTX1080 TI, I had this problem 2 weeks ago, it was really annoying with all those random DX Fatal error crash, but it all happened after an update of the Nvidia driver from Windows, so I reversed it and made the update again and it seems to have fixed the issue. Maybe it's something with Nvidia. ? Also playing in 4k with graphics set to max so the FPS is not much higher than 60-65 and a bit lower in Eureka when doing a NM with the train on it. But maybe there is multiple causes to it and FPS can be one. But in my case I'm pretty sure that it was my drivers, so it can be a good thing to reinstall them ?