Nehalem)

Introducing a New Dynamically and

Design-Scalable Microarchitecture

that Rewrites the Book on Energy

Efficiency and Performance

Since the introduction of Intel® Core™

microarchitecture in 2006 and its 2007

45nm enhancements—the Intel Core

microarchitecture (Penryn) family of

processors—the blistering performance

and energy efficiency of Intel® microprocessors

have delivered unprecedented

capabilities to computer users. Now a new

microarchitecture named Nehalem (the

foundation of the Intel® Xeon® processor

3500 and 5500 series) builds on these

earlier microarchitectural marvels, rewriting

the book on processor scalability, performance,

and energy efficiency.

The first chapter is all about scalability.

Intel® microarchitecture (Nehalem) is a

dynamically scalable and design-scalable

microarchitecture. At runtime, it dynamically

manages cores, threads, cache, interfaces,

and power to deliver outstanding energy

efficiency and performance on demand.

At design time, it scales easily, enabling

Intel to provide versions optimized for

each server, desktop, and notebook market.

Intel will deliver versions differing in the

number of cores, caches, interconnect

capability, and memory controller capability,

as well as in the inclusion of an integrated

graphics controller. This allows Intel to

deliver a wide range of price, performance,

and energy efficiency targets for servers,

workstations, desktops, and laptops.

Intel microarchitecture’s (Nehalem’s) energy

efficiency and performance comes at a

critical crossroads in computing. In the

past, when a computer’s energy efficiency

wasn’t a concern, nearly every architecture

feature that could improve processor

performance would be included without

worrying about the power cost. But in

an age of increasing concern for limited

resources and increased energy costs,

every segment (server, workstation,

desktop, and mobile) is power-constrained

and designing a microarchitecture requires

a different approach. Processor manufacturers

must consider the power cost for

whether the processor is intended for the

home, data center, or ultra-light laptop.

Intel weighed every architectural

feature added to Intel microarchitecture

(Nehalem) against a strict power/performance

efficiency threshold. If the feature

couldn’t add more than a one percent

performance gain for a less than three

percent power cost, Intel wouldn’t add it.

By measuring the benefit of the performance

gain against the power cost, Intel

was able to design Intel microarchitecture

(Nehalem) to deliver greater power

efficiency at any power envelope.

Jeff Casazza

Intel Corporation

“By measuring the benefit

of the performance gain against

the power cost, Intel was able

to design Intel microarchitecture

(Nehalem) to deliver greater power

efficiency at any power envelope.”