(Mac II) A version of Apple' s Macintoshpersonal computer, released in March 1987, using the MotORola 68020CPU, 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 NuBusexpansion slots fOR additional peripheral and coprocessOR boards. (1996-05-25)