The driver auto-detects all device information necessary to initialize the card. The only lines you need in the "Device" section of your XF86Config file are:
Section "Device" Identifier "Intel i810" Driver "i810" EndSectionor let
xf86config do this for you.
However, if you have problems with auto-detection, you can specify:
In order to use most resolutions, it is necessary to install the 'agpgart.o' module. You will probably have to compile the module yourself (see the notes in the module).
Note: the i810 driver detects whether your motherboard has display cache video memory. This memory is has reduced bandwidth compared to normal system memory, and isn't used by the server. The main function of this memory is for ancillary buffers (eg. z buffer) in a forthcoming 3d capable server.