Macintosh IIvi

The Macintosh IIvi (also sold as the Macintosh Performa 600) is a personal computer designed, manufactured, and sold by Apple Computer from September 1992 to February 1993. The IIvi was introduced alongside the Macintosh IIvx, using a slower processor (16 MHz vs. 32 MHz) and no floating point unit. The Performa 600 models, meanwhile, are the IIvi with the IIvx's 32 MHz CPU. The IIvi was, on some benchmarks, faster than the IIvx. It is the only model in the Macintosh II family to be branded as a Performa.
This model was discontinued four months after its introduction, when the Centris 650 was introduced at a similar price point.
Models.
All models include three NuBus slots and a Processor Direct Slot (PDS). 
The Performa 600 models were formally introduced on September 14; shipments were delayed until October to coincide with the introduction of the IIvi and IIvx.
Introduced September 14, 1992:
Introduced October 19, 1992: