I suggest you try with Project64 and Jabo's Direct3D6 plugin. SiS chips are for the most part really old and quite poor for gaming, be it modern PC gaming or emulating 3D graphics hardware (3D capabilities are piss poor, or rather unreliable at best, and it's more geared towards 2D).
In any case, at least make sure that you've got the latest graphics driver for your chip from SiS' homepage.