you can find infos about power consumption in the fromer version of the Power calculator, this might help you to verify if it might make sense to go virtual (it might make sense I`m sure *g)
The actual and former version can be accessed via http://www.dell.com/content/topics/topic.aspx/global/products/pedge/topics/en/config_calculator?c=us&l=en&cs=555 the new one is more granular due to exact creating config, but it only contains the actual servers (ESSA).
The former version of DCCP is 3.04 , the 850 is listed, but the pe 650 isnt
the technical specification can be found at http://support.dell.com/support/edocs/systems/pe650/en/ug/n1515aa0.htm PE 650
The manual can be found at http://support.dell.com/support/edocs/systems/pe650/en/ug/index.htm