A computing device includes a low power auxiliary processor, such as a processor on a wireless card or sub-system, which is able to takeover processing in place of the computing device's central processing unit (CPU). Operating the computing device on the auxiliary processor draws less power from the computing device battery, enabling extended operation in an auxiliary processor mode. When in this mode, the auxiliary processor controls peripherals and provides the system functionality while the CPU is deactivated, such as in off, standby or sleep modes. In the auxiliary processor mode, the computing device can accomplish useful tasks, such as sending/receiving electronic mail, displaying electronic documents and accessing a network while drawing minimal power from the battery. Transitions between the normal operating mode and auxiliary processor mode may be transparent to users. Such a computer may display instant on, always on and always connected operating features.