Mirror’s Edge actually had a place with tons of broken glass falling down, where the framerate would drop into the single digits if it used CPU PhysX. I remember that because it shipped with an outdated PhysX library that would run on the CPU even though I had an Nvidia GPU, so I had to delete the game’s PhysX library to force it to use the version from the graphics driver, in order to get it to playable performance. If you didn’t have an Nvidia driver you would need to disable PhysX for that segment to be playable.