i also run 3.4.8 with the latest 3Dview.
and it seems to work perfect no problem.
did you allready lookt at the Rendering options if the Lightbeam is on?
otherwise i have no clue.
AMD FX-6100 (3.6ghz)x6, Nvidia 770GTX 4GB, 8GB Ram,ROG MB, enttec Pro, Open enttec, Velleman, T2250MTS-B1 22"touchscreen, Ilyama 23" screen, scans, dimm, rgbled, laser, soundsystem Just a drive-in show. Live and Dance