Original 45nm Intel® Core™ Microarchitecture

Power Management Enhancements in the 45nm Intel® Core™ Microarchitecture

INTRODUCTION

The Penryn family of processors, implemented in a 45nm high-k metal gate silicon process technology, is designed to fit a wide range of power envelopes and market segments. Energy efficiency (energy consumed for doing a unit of work) is significantly improved due to process power scaling and innovative architectural power-management features. Power scaling enables better performance and higher power efficiency in most workloads, and the power-management features primarily enable lower idle power that leads to an overall reduction of platform energy consumption. Lower idle power helps improve battery life in mobile platforms, allows platforms based on the Penryn family of processors to meet or exceed Energy Star and other regulatory requirements for idle power consumption in desktop PCs, and lowers electricity and cooling costs for servers. The details of the 45nm high-k metal gate process technology and its power benefits are discussed in the last issue of the Intel Technology Journal [1,2] and hence are not covered here in detail. In this paper we focus on the architectural innovations in the power-management domain of the Penryn family of processors.

The Penryn family of processors builds upon the power-management capabilities of the core microarchitecture. The Advanced Configuration and Power Interface (ACPI) specification [3] describes the processor sleep states and performance states in detail. When the processor is executing instructions, it is in the C0 active state. The C1, C2 states, etc. are successively lower-power processor sleep states in which no instructions are being executed. P states are processor performance states defined by the processor frequency. The Penryn family of processors supports the Core Microarchitecture C states, P states, and thermal monitoring functions. In addition, the Penryn family of processors introduces several new key features and extends some of the existing mobile platform capabilities to desktop systems. Two key features introduced in the Penryn family are as follows:

• Deep Power Down (DPD), a new idle power state.
• Enhanced Dynamic Acceleration Technology (EDAT), a feature to increase Single Threaded (ST) performance by using the power headroom of the idle core. A simpler version of this feature is also available in the later versions of the Intel® Core™2 Duo 65nm processor.
• Power Management features extended to other segments are as follows:
• The Deeper Sleep state is now available in desktop platforms and in quad-core products.
• A version of the Deep Sleep state (called CC3 or Core-C3) state is now available in server platforms.
• The Enhanced Dynamic Acceleration Technology (EDAT) and Deeper Sleep state technology were extended to the mobile Quad-Core Extreme Edition product.

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