I was going over Server Technology's white paper on Planning, Implementing and Application of Cabinet Power Distribution Units, and found a useful set of links for power calculator from Server vendors.
The power ratings found on the product nameplates are notoriously high when compared to its actual power consumption. The reason for this is that manufacturers design power supplies to be used across multiple product lines and also in anticipation of additional features and upgrades in the future. Best practices are to check the equipment manufacturers' website to see if they have real-world power loads and capacities available. See Appendix A for a listing of power calculator tools available from Cisco, Dell, HP, IBM and Sun.
Power Calculation Tools
Power Calculators are available but not in one centralized location. At www.sun.com use their search feature and query for "Power Calculator"
The Dell Web based tool on above site is informative.
Energy efficiency is not just a problem of power (kWh), not just a problem of cooling (BTUs), not just a problem of performance (MIPS) and not just a data center issue — it's all of the above. It is your ultimate challenge. We believe it's time to confront all of these issues all together. To get started, use Dell's Data Center Capacity Planner to better understand your "Green print."