  Electrical power requirements will be a constraint on the future growth of
Distributed High Throughput Computing (DHTC) as used by High Energy Physics.
Performance-per-watt is a critical metric for the evaluation of computer
architectures for cost- efficient computing. Additionally, future performance
growth will come from heterogeneous, many-core, and high computing density
platforms with specialized processors. In this paper, we examine the Intel Xeon
Phi Many Integrated Cores (MIC) co-processor and Applied Micro X-Gene ARMv8
64-bit low-power server system-on-a-chip (SoC) solutions for scientific
computing applications. We report our experience on software porting,
performance and energy efficiency and evaluate the potential for use of such
technologies in the context of distributed computing systems such as the
Worldwide LHC Computing Grid (WLCG).
