Does low-power design imply energy efficiency for data centers?

Data center efficiency has quickly become a first-class design goal. In response, many studies have emerged from the academic community and industry using low-power design to help improve the energy efficiency of server hardware. Generally, these proposals hold the assumption that low-power design is inherently better for energy efficiency; this preconception stems mostly from great success in the mobile space with building low-power, energy-efficient systems. We observe that unlike mobile devices, constraining a data center server to a low power budget is arbitrary and higher power design choices can be more energy efficient. We analyze the energy efficiency design space of past commercial server designs and find that high-power servers are generally more energy efficient than low-power ones. Furthermore, we evaluate building low- or high-power server clusters and find that the small increase in the cost of cooling high-powered servers is easily outweighed by their greater efficiency.