08 MAXIMUMPC JANUARY 2007
W
hen your competitor has you on
the ground with a quad-core boot
at your throat, do you tap out or bust an
unexpected move?
With its own quad-core chips more than
half a year away, AMD’s surprise maneuver
is the Quad FX platform, which accommo-
dates any of the company’s newly minted
dual-core processors—Athlon 64 FX-70,
FX-72, or FX-74— in tandem. In other words,
dual dual-cores.
The Quad FX platform essentially
repurposes a dual-Opteron confi guration
with a few key differences. The fi rst is
RAM. Dual-processor Opteron machines
generally require registered system mem-
ory, which uses a small chip to ensure
signal integrity with large amounts of RAM.
These registers are valuable when running
16GB of RAM with mission-critical appli-
cations, as you would in a server, but they
actually impede performance on desktop
machines. The Quad FX does away with
the need for registered RAM.
The Quad FX platform will also not be
compatible with Socket AM2 CPUs; the
Athlon 64 FX-7X procs use a new Socket
1207 interface. And even though the inter-
face is pin-compatible with Opteron CPUs,
it’s not electrically compatible. AMD says ithas disabled Opteron support in the Quad
FX for marketing purposes. AMD offi cials
acknowledge that this is even more of
a kludge quad-CPU design than Intel’s
Kentsfi eld, but they point to the future.
Next year, when AMD’s quad-core chips
are out, a Quad FX will be able to run a
total of eight execution cores by utilizing
two quad-core CPUs.
There’s a price, of course. The top-end
3GHz FX-74 will run about $1,000 for a pair,
and the Asus dual-processor motherboard
using the Nvidia 680a chipset is expected
to top $300. Consumers will also have to
equip a machine with two heatsinks, four
sticks of RAM, adequate cooling for the two
125-watt processors, and a power supply
capable of running all this plus the GPUs.
In the end, such a rig might end up costing
at least 25 to 30 percent more than a com-parable Intel quad-core machine.
PC analyst Rob Enderle takes a gener-
ally bullish stance on the platform, but says
the fi nal verdict on AMD’s Quad FX won’t
come until the benchmarks are run.
According to Enderle, for Quad FX to
be it success, “it can be slower and less
expensive [than Intel’s solution], it can be
the same speed and less expensive, but it
can’t be more expensive and slower.” He
adds that given AMD’s target audience,
the overkill aspect of the Quad FX actually
works to its advantage. Enthusiasts might
also be attracted to the ability to build a
system with one CPU now and add another
later, he says.
Quad FX machines are expected to be
available when you read this; look for our
coverage of how well the technology stacks
up in the next issue of Maximum PC.AMD’s
Quad FX
Can a machine that houses
two distinct dual-core
processors compete with
Intel’s quad-core rigs?
That’s what AMD is aiming
for with its high-end Quad
FX platform, which lays the
foundation for octo cores
next year
quick start THE BEGINNING OF THE MAGAZINE, WHERE ARTICLES ARE SMALL
A pair of the new dual-socket-capable dual-core Athlon 64 FX-74s gets four cores
into your AMD machine.CLOCK SPEED 3GHz 2.8GHz 2.66GHz
L1 CACHE 128KB 128KB 64KB
L2 CACHE 2MB total 2MB total 8MB total
EXECUTION CORES 2 2 4
PROCESS TECHNOLOGY 90nm 90nm 65nm
TRANSISTORS 227 million 227 million 582 million
DIE SIZE 235 mm^2 230mm^2 286mm^2
PRICE PER 1,000 $1,000 (per pair) $713 $1,
TDP 125 watts (per CPU) 125 watts 130 watts
DUAL SOCKET COMPATIBLE? Yes No NoSPECS
ATHLON 64 ATHLON 64 INTEL CORE
FX-74 FX-62 QX