In the 640×350 high resolution mode, which requires an enhanced EGA monitor, 16 colors can be selected from a palette comprising all combinations of two bits per pixel for red, green and blue, allowing four levels of intensity for each primary color and 64 colors overall. The 640×200 and 320×200 graphics modes provide backwards compatibility with CGA software and monitors, but permit use of all sixteen colors in the CGA palette simultaneously, instead of the fixed four colors available in those modes on the actual CGA.