"One of the biggest claims to fame for asynchronous logic is that it consumes less power due to the absence of a clock. Clock power is responsible for almost half the power of a chip in a modern design such as a high-performance microprocessor. If you get rid of the clock, then you save almost half the power. This argument might sound reasonable at a glance, but is flawed. If the same logic was asynchronous, then you have to create handshake signals, such as request and acknowledgment signals that propagate forward and backwards from the logic evaluation flow. These signals now become performance-critical, have higher capacitive load and have the same activity as the logic. Therefore, the power saving that you get by eliminating the clock signal gets offset by the power consumption in the handshake signals and the associated logic."
