Power reduction techniques for an 8-core xeon® processor

This paper presents the power reduction and management techniques for the 45 nm, 8-core Nehalem-EX processor. Multiple clock and voltage domains are used to reduce power consumption. Long channel devices and cache sleep mode are used to minimize leakage. Core and cache recovery improve manufacturing yields and enable multiple product flavors from the same silicon die. Clock and power gating minimize power consumed by disabled blocks. An on-die microcontroller manages voltage and frequency operating points, as well as power and thermal events. Idle power is reduced by shutting off the un-terminated I/O links and shedding phases in the voltage regulator to improve the power conversion efficiency.