In the mid 1980?s the power growth that accompanied scaling forced the industry to focus on CMOS technology, and leave nMOS and bipolars for niche applications. Now 20 years later, CMOS technology is facing power issues of its own. After first reviewing the ?cause? of the problem, it will become clear that there are not easy solutions this time ? no new technology or simple system/circuit change will rescue us. Power, and not number of devices is now the primary limiter of chip performance, and the need to create power efficient designs is changing how we do design. This talk will review power optimized design methods and shows how power is strongly tied to performance and that variability aversely effects power efficiency. Projecting forward, it shows that unless die size shrinks, in future technologies most of the devices will need to be idle most of the time which has strong ramifications for the both the underlying device and system design.