The MC68060 delivers up to 3 times the performance relative to its predecessor, the MC68040. Furthermore, the MC68060 bus is very similar in comparison to the MC68040 bus. A socket adapter from Interconnect Systems is available that converts the MC68060 bus to operate in some existing MC68040 systems. For these reasons, the MC68060 is a viable upgrade processor to an existing MC68040-based system.However, to achieve the aggressive performance target, the MC68060 leaves some instructions unimplemented to streamline internal operations. This article discusses in detail the differences between the MC68060 and the MC68040 from a software perspective and discusses the software challenges that may arise when porting software to the new MC68060.