Selecting the most energy efficient computer chips should be at the heart of any attempts to cut datacentre energy use, according to a recent report from consultancy Emerson.

The Energy Logic report argues that while attempts to optimise cooling and improve server utilisation have a role to play, a "cascade effect" means that it is the energy efficiency of server hardware that has the greatest effect on energy use.

"Reductions in energy consumption at the IT equipment level have the greatest impact on overall consumption because they cascade across all supporting systems," the report claims. "Every watt of savings that can be achieved on the processor level creates a total of 2.84 watts of savings for the facility."

The report estimates that US datacentres' energy costs stand at $3.3bn a year. However, it cites research from the Environmental Protection Agency that claims this figure could be halved by 2011 if firms adopted datacentre management best practices.

Emerson's report outlines 10 of these best practices, including adoption of more energy efficient processors and power supplies, wider roll out of advanced cooling technologies, and greater use of power management and server virtualisation software.