The Xconfigurator as well as xf86config identify the video chip as cirrus logic 542X. They show the different modes available (8bpp, 16bpp & 24bpp) however when i try to run startx in 16bpp, 640x480 mode, the server crashes, saying this mode is not available. I have 1Mb video ram.
The Cirrus Logic driver requires additional options to be added the the /etc/X11/XF86Config file to allow for 16bpp color and above. For directions on how to do this please refer to http://www.xfree86.org/3.3.2/cirrus.html