Macintosh II Mac II <computer> (Mac II) A version of {Apple}'s {Macintosh} {personal computer}, released in March 1987, using the {Motorola 68020} {CPU}, which runs at a higher {clock rate} than the {Motorola 68000} used in the original Mac. The Mac II has a full 32-bit data bus instead of a 16-bit bus. Mac II models have built-in 40 to 160 megabyte {hard disks} and can take up to eight megabytes of {RAM} (and more as denser memory chips arive). The Mac II was the first Macintosh to provide a colour graphics option, with up to 256 colours on screen at a 640x480 resolution. Mac II models are designed for expandability with three ({Macintosh IIcx}) or six (II & IIx) built-in {NuBus} {expansion slots} for additional {peripheral} and {coprocessor} boards. (1996-05-25)