The first requirement for improving energy efficiency in the data center is the development of reliable metrics for comparison of energy-efficiency performance. This has been problematic as previous metrics have concentrated on performance per watt at just single points along the loadline -- such as all the data center’s servers at idle or at 100% utilization. Neither of these points are an accurate measure of real-life usage since the amount of work each server does can vary greatly depending on its function and usage. A more reliable metric is to measure the entire loadline of all the servers for a day, week and month, determining the total compute output as a ratio of total power consumed in the entire data center.