When is the last time that PC had a good cleaning, I.E Reformat? It might just be time to start squeaky clean. I'd really ponder it at this point.
But, that is a cop out, and it really could be a N3V thing, or something playing foul on the side of injection. Sometime tells me the way TR19 overlay for HUD is coded is causing some issues obviously, on practical hardware.
Can you also try NOT running ANY monitoring software, no On Screen Display (OSD), no Geforce Experience, no Shadowplay. Just use Task Manager to monitor usage and loads under Performance. Still do it?
Something just tells me two OSDs are playing a fighting match behind the scenes somewhere. The games, and something else. Just a hunch from similar problems I had in various games in QA days.
This has been mentioned before numerous times and it's not just related to TRS19.
If anyone wants to check frame rates in the game, there's something already built-in called the profiler. Click on the Developer menu item on the Launcher, or on Content Manager for that matter, and choose Show Profiler.
What this does is open a small window with stuff in it. A lot this stuff doesn't make much sense to us, but more importantly at the top part is the frame rates! Yes we can monitor the frame rates in the game using a built-in utility, and I did compare them to my EVGA PrecisionX OSD, and the were the same. I then canceled the EVGA one because it did cause extra stuttering. The system monitoring bug is a known issue with Windows 10.