I pay attention to the numbers and how the video actually looks. A red but locked 30fps will look better than 45fps with stutters. And by stutters, I usually refer to panning the camera around. The sim could fly smooth with a fixed camera view, but see stutters when panning the camera.
Side note if you use an Xbox style controller: When panning and the center dot crosses a cockpit control, the sim will slow the panning action (something I hate). That isn’t the same as stuttering, so aim the camera outside the window or use an external view.