1. A method to manage power usage of a data center via an application level interface, comprising: determining, for respective nodes within the data center, a power consumed by a graphics engine of the node operating in a first graphics state during a first time of operation; aggregating the power consumed by the graphics engines of the respective nodes to determine a power consumed by the data center during the first time of operation; comparing the power consumed by the data center with a data center power threshold value retrieved via the application level interface; when the power consumed by the data center satisfies the data center power threshold value, comparing, for the respective nodes, the power consumed by the graphics engine of the node during the first time of operation with a node power threshold value associated with the node; and when respective ones of the nodes satisfy corresponding ones of the node power threshold values, setting the graphics engine of at least one of the respective ones of the nodes to a second graphics state to cause the data center to comply with the data center power threshold value.