To calculate the amount of SXDRAM to reserve, add up the individual requirements and round up to the next multiple of 1 MByte. The individual requirements are:
The XGL Z buffer requires 4 bytes per pixel. The XGL back buffer is required only for RGB double buffering, and is also 4 bytes per pixel. For example, if the application uses an animated 24-bit Z-buffered raster that is limited to 900 x 900 pixels, then the SXDRAM requirement is 900 x 900 x 8 = 6480000 £ 7 MBytes (1048576 x 7 bytes).