The Cisco 3900 series, Cisco 2900 series, and Cisco 1900 series integrated services routers generation 2 (ISR G2) have hardware and software features for reducing power consumption. The hardware features include high-efficiency AC power supplies and electrical components with built-in power saving features, such as RAM select and clock gating. See your router's hardware installation guide for more information on these hardware features. The software features include EnergyWise, a power efficiency management feature that will power down unused modules, and disable unused clocks to the modules and peripherals on the router. ISR G2s must be running Cisco IOS Release 15.0(1)M or later to support EnergyWise. Detailed configuration procedures are included in the Cisco EnergyWise Configuration Guide, which can be found at Cisco.com.
The following sections provide general information about the EnergyWise feature running on ISR G2s: