Low Power or High Performance? A Tradeoff Whose Time Has Come (and Nearly Gone)

Some have argued that the dichotomy between high-performance operation and low resource utilization is false --- an artifact that will soon succumb to Moore's Law and careful engineering. If such claims prove to be true, then the traditional 8/16- vs. 32-bit power-performance tradeoffs become irrelevant, at least for some low-power embedded systems. We explore the veracity of this thesis using the 32-bit ARM Cortex-M3 microprocessor and find quite substantial progress but not deliverance. The Cortex-M3, compared to 8/16-bit microcontrollers, reduces latency and energy consumption for computationally intensive tasks as well as achieves near parity on code density. However, it still incurs a ~2× overhead in power draw for "traditional" sense-store-send-sleep applications. These results suggest that while 32-bit processors are not yet ready for applications with very tight power requirements, they are poised for adoption everywhere else. Moore's Law may yet prevail.