I just did a quick circuit at KBTV, and didn’t notice any massive frame drops. I went from 60 into the low 40’s at worst, even when I was thrashing my view about in the external camera.
If you move the camera very slowly as you orbit, which I would imagine is far easier with a controller joystick than with a mouse, you see no frame dips whatsoever. If you do it quickly you do get the dips. Which leads me to believe the so-called scenery pre-caching isn’t actually working properly, as it did before SU5, even when set to Ultra.