I wished that virtual/onboard mirrors could be more configurable, because some tracks and cars combinations I really need to even turn them off to not dip under 60 fps. Maybe framerate could also be configurable and I am sure it would help, just like ACC does, I don't need the full fps rate on the mirrors or high quality, I just want to see what's behind and to the sides, and some times I can't do it. For some people it should be even worse, as I just got a relatively better GPU recently and before, at night or headlights active for AI, all tracks I needed to do that. Shouldn't be that hard.
I´ll add to this and say mirrors´ FOV and position should be indepenent of the seat position and fov, at least the virtual ones. I don´t see the point of having adjustable seat placement if some of the extreme positions, which suit some screens/fovs better, render the mirrors unusable no matter how much you adjust them.
Try setting this line to 0. I've had it set to this and haven't needed to adjust mirrors since using this setting. "Moving Rearview":0, "Moving Rearview#":"Whether mirrors respond to head movement in cockpit (0=none, 1=position-only, 2=FOV-only, 3=both) - add 4 if you want to IGNORE head-tracking movement",
