face animations... inconsistent?

currently, i play the game on minimum detail with max texture quality. whenever i roll into a cutscene, the facial animations seem to be very inconsistent. sometimes the face moves, and sometimes it doesn't. when they do move, only the mouths open and close for a split instant.

does the facial animations depend on how high you turn your visual quality, or is it a problem with the graphics card?

i'm using a geforce fx5500 PCI with 256mb.