It replaced the 16 MHz Motorola 68020 CPU and 68881 FPU of the II with a 68030 CPU and 68882 FPU (running at the same clock speed); and the 800 KB floppy drive with the 1.44 MB SuperDrive (in fact, it was the first Mac to have one).
Notable computers including 68881 or 68882 FPUs included the Sun 3 from Sun Microsystems, the Macintosh II family of computers from Apple Computer, the NeXT Computer, parts of the Atari family (Mega STE, TT and Falcon030) and the Commodore Amiga 3000.