Controlling a vehicle comprises: providing, from an activation port, an activation signal for activating control of at least one of one or more electronically controllable devices during a high-speed activation time interval; and managing power consumed by an integrated circuit that includes two or more processor cores during the high-speed activation time interval. The managing includes: receiving the activation signal from the activation port, in response to the activation signal, executing at least a portion of stored code by a first subset of fewer than all of the processor cores at a first power level, and after the high-speed activation time interval, executing at least a portion of the stored code by a second subset of one or more of the processor cores at a second power level lower than the first power level.