MaximumPC 2001 11

QUICKSTART^

THE BEGINNING OF THE MAGAZINE, WHERE ARTICLES ARE SMALL

08 |MAMAMAXIMXIMXIMXIMUUUUMMPPPCC|JAN 2011 |www.maximumpc.com

N

uclear fusion involves smashing small

atoms together to release incredible

amounts of power. That’s likely what

AMD hopes to unleash when its next-generation

Fusion processors hit the street in early 2011.

Dubbed an Accelerated Processing Unit,

or APU, Fusion fuses one or two x86 cores with

a fairly powerful graphics core in an eff ort to

dominate Intel’s popular but woefully under-

powered Atom chips. And while it can’t take on

the mighty Nehalem-microarchitecture chips in

x86 performance, Fusion can defi nitely apply a

serious amount of pain to Intel’s Achilles’ heel in

the form of integrated-graphics performance.

Four Fusion chips will initially be off ered

in the “Brazos” family, featuring single- and

dual-core confi gurations: Two “Zacate” chips

and two “Ontario” chips. Diff erent core clock

speeds as well as GPU clocks will diff erentiate

the chips, as will power consumption.

Fusion’s CPU is nothing too revolutionary

from a pure x86-performance perspective.

The company freely admits that the pair of

x86 cores in Fusion off ers about 90 percent the

performance of an original Athlon 64. In fact,

in some compute-intensive chores, Fusion may

perform even worse since the core has been

tweaked from a three-issue design to a two-

issue design. In layman’s terms that means the

core is narrower than Athlon 64’s. By compari-

son, one of the key performance advantages

that Intel’s Core 2 had over Athlon 64 (among

others) was its wider four-issue core. AMD said

it went with a narrower core design to reduce

power consumption.

The company said an improved branch pre-

dictor and a “well-managed” out-of-order engine

help keep the performance of the chip at better-

than-Atom levels. And that’s really the point of

Fusion. These chips won’t set the world on fi re

but they should outgun equivalent Atom parts.

But we digress. Ultimately, Fusion is not

so much about x86 performance as it is about

graphics. That’s where AMD is putting its

money in the fi rst Fusion chips. Sporting a

third-generation unifi ed video-decoder core,

DX11 capability, support for H.264, Divx, and

Xvid, and housing 80 so-called “nanocores,” the

fi rst Fusion chips will have roughly the graphics

performance of a Radeon HD 5450.

That might not seem like much to a person

rocking a Radeon HD 5970, but remember,

we’re talking about a mobile chip that’s incred-

ibly tiny. The x86 cores and GPU, along with

the integrated memory controller, integrated

PCI-E, and other platform interfaces measures

roughly 75mm^2 on TSMC’s 40nm process

technology. Intel’s current D-series Atom

measures 87mm^2 on the company’s 45nm

process technology.

Anyone who has ever used an Atom—

even the current-generation chips—can attest

to their sluggish performance. And that’s at

x86. Toggle over to anything graphics-related

on an Atom and the space/time continuum will

literally start running backward, it’s so slow.

To be fair, Intel’s graphics have always acted

more like anti-accelerators. That’s not so with

Fusion. We’re prohibited from disclosing raw

numbers right now, but we can say that Fusion

is no Atom, or even Arrandale, in graphics

performance. You can actually play some fairly

modern games—if you’re open to dropping the

resolution a bit.

For example, we were able to play the

hit game Call of Duty: Modern Warfare 2

at 1280x768 resolution with Fusion. Try

doing that on a sub-$500 notebook with

integrated graphics.

AMD’s messaging on power consumption

is also promising. With the Zacate version of the

chip, the company thinks worst-case power con-

sumption will be 18 watts. On the test platform

The 40nm-based Zacate Fusion chip packs dual

x86 cores along with an 80-“nanocore” GPU, an

integrated memory controller, and eight PCI

Express lanes.

THE NEWS

Hands-on preview of AMD’s fi rst ‘Accelerated Processing Unit’ —GORDON MAH UNG

Fusion: AMD’s Atom Smasher

THE NEWS

Fusion: AMD’s Atom Smasher

THE NEWS

SIMD

Engine

Hudson

x

Processor

x

Processor

SIMD

Engine

Platform Interfaces

Unified Media Interface

HDMI

Two DDR3 DIMMS

DVI

VGA

PCI-E

1.0 x 4

CIR

USB

Unified Video

Decoder

High

Performance

Bus and

Memory

Controller

SATA

LPC

SPI

PCI-E 1.0 x 4

HD Audio

Two sets of PCI-E

interfaces are

available: Four

PCI-E 1.0 lanes

off the APU and

another four off

of the Hudson

south bridge.

BRAZOS BLOCK MAP