October 1991 saw the introduction of Macs using Motorola's high-octane 68040 CPU. The Quadra 900 was a full-fledged tower design, although it had only a single available front accessible drive bay. The Quadra 700 and 900 were the first Macs with built-in ethernet, using Apple's AAUI connector. The 900 was replaced by the 33MHz 950 in May 1992.