  Motivated by the massive energy usage of blockchain, on the one hand, and by
significant performance improvements in low-power, wimpy systems, on the other
hand, we perform an in-depth time-energy analysis of blockchain systems on
low-power nodes in comparison to high-performance nodes. We use three low-power
systems to represent a wide range of the performance-power spectrum, while
covering both x86/64 and ARM architectures. We show that low-end wimpy nodes
are struggling to run full-fledged blockchains mainly due to their small and
low-bandwidth memory. On the other hand, wimpy systems with balanced
performance-to-power ratio achieve reasonable performance while saving
significant amounts of energy. For example, Jetson TX2 nodes achieve around 80%
and 30% of the throughput of Parity and Hyperledger, respectively, while using
18x and 23x less energy compared to traditional brawny servers with Intel Xeon
CPU.
