Very glad to see you pick up this important issue of defining useful work/productivity in the data center. At Emerson Network Power we feel that the Green Grid has taken a bold step forward in offering these proxies to the industry for further evaluation. We strongly encourage those interested to download the white paper, Proxy Proposals for Measuring Data Center Efficiency, and provide feedback and recommendations to the Green Grid via the on-line survey tool. It is now time for all of us with an interest in developing a meaningful metric to report data center productivity to become fully engaged and constructively speak our mind on their relative merits.

One observation to note: all of the proxies will favor newer servers as this is just the inherent nature of our business. Newer devices are more productive in not only total capacity but also capacity per watt. This gives further credence to your observation on PUE not being relevant as a data center with a PUE of 1.2 comprised of servers three to five years old will never match a data center with a PUE of 2 and all new servers from a productivity standpoint. And productivity is what moves business. One can see the impact of this in the complete CUPS proxy white paper

One observation to note: all of the proxies will favor newer servers as this is just the inherent nature of our business. Newer devices are more productive in not only total capacity but also capacity per watt. This gives further credence to your observation on PUE not being relevant as a data center with a PUE of 1.2 comprised of servers three to five years old will never match a data center with a PUE of 2 and all new servers from a productivity standpoint. And productivity is what moves business. One can see the impact of this in the complete CUPS proxy white paper.