Macintosh Quadra

The Macintosh Centris line was merged with the Quadra in October 1993, adding the 610, 650 and 660AV to the range.

The AV models also introduced PlainTalk, consisting of the text-to-speech software MacinTalk Pro and speech control (although not dictation).

Lexicon chose the name Quadra hoping to appeal to engineers by evoking technical terms like quadrant and quadriceps.

Apple partially fixed this by having the basic Mac OS memory copy call flush the caches.

This solved the vast majority of stability problems, but negated much of the Motorola 68040's performance improvements.

The net effect of this was that many complex applications were initially slow or prone to crashing on the 68040, although developers quickly adapted to the new architecture by relying on Apple's memory copy routines rather than their own (or flushing the cache) and using the memory copy that did not flush the cache when appropriate (most of the time).