I followed last weekend all your suggestion, many thanks for them. But tbh, it doesn`t matter (at least for me...), when i`m using all your suggestion incld. the older nvidia driver, or just use the default nvidia and inspector settings and the latest driver. As i dont have any similar issues with other simracing title, i would (in the meanwhile) guess, that the main issue is rf2 itself...
The 'graphical' symptom (skipped frames etc) might not be anything graphical. I think rF2 runs the whole user input -> physics calculations -> graphical output loop faster than other titles, and needs everything to stay up to speed to maintain that loop in realtime. (It's probably even fair to guess that many less 'simmy' titles/games don't really have the player in the loop at all - they just take user input whenever it arrives, and otherwise just keep the world running or wait and deal with the delay as it happens) If we say that loop is running at 100Hz, a background process that only uses 2% CPU each second, but does that 2% in one continuous chunk, could stop rF2 for two entire loops. It could then take a number of loops to catch back up to realtime. This is why the in-game Ctrl-C graph showing CPU use for graphics and physics is much more useful than any external CPU usage tools, because it reflects the CPU availability for the game itself. Unfortunately I think this means tracing the cause of pauses/stutters can be rather difficult, because it's not something that's going to stand out as being a resource hog. And any underlying system issues only need to be minor to affect how rF2 runs. Figures above are a wild guess, but hopefully the concept is somewhat close.
To make it short, borderless / windowed mode did the trick for me to stop the stutters / freezes. It was so much annoying to have a new high end PC ( Intel i7 4GHz, Geforce GTX 1070, M.2 x4 SSD, .. ) and the only ( and my favorite ) simulator that suffered stutters was rFactor 2. Racing, especially online was no fun anymore. Leaving the pit became a nightmare - when someone entered a server the screen froze a few seconds, most of the time my car ending in a wall. More upsetting was, that even I am an experienced user / developer, it took me weeks to find a solution. In the mean time I reinstalled rF2, clean installed nVidia drivers, Win10, deactivated nVidia sound devices, deactived Steam and nVidia Share overlays, measured GPU and CPU usage etc. Nothing helped. I still don't know the root cause for the stutters in fullscreen mode, that just occur with rFactor 2. But I am able to race again.
I got for a short períod of time those 1 sec freezes. What i did was look for the Windows process manager while i'm playing, and bingo... Every time an application of my internet banking uses more than 50% of CPU i has the freeze. Just uninstalled the application. But i'm think that you set rf2 process for higher priority may solve too. @depor did you solved the problem?
