The frame buffer uses an INMOS IMS G332 RAMDAC with a 256-entry 24-bit color look up table, which selects 256 colors for display out of a palette of 16, 777, 216.
2.
There is generally no need for a color look up table ( CLUT, or palette ) when in high color mode, because there are enough available colors per pixel to represent graphics and photos reasonably satisfactorily, although the lack of precision decreases image fidelity.