JUNE 2004 MAXIMUMPC 31
proc PC. Photoshop 7.0 offers pretty
much the same story: Only in certain
filters does the application warm up
the second processor. Most of the
time, the extra $800 you spent is just
draining electricity.
Does this mean two CPUs aren’t
worth the money? Not necessarily. If
you have a need for the few applications
that actually use two processors to their
fullest extent, the money is well spent.
One case in point is Newtek’s LightWave
3D 7.5. This pro-level modeling and
rendering app runs about 100 percent
faster with a second processor. We
also saw the second processor pay
off reasonable dividends in SYSmark
2004 , where the score jumped by
about 25 percent (proof that the new
SYSmark 2004 is far better than its
predecessor at measuring the
performance impacts of
multitasking).
Indeed, dual processors do make
a difference if you run, say, Microsoft
Word , an antivirus scanner, and an
MP3 encoder at the same time. In
fact, multitasking is the number one
reason to run a dual-proc box.
Something the benchmark numbers
don’t make clear is the “smoothness”
that dual-proc users experience. While
it’s easy to choke up a single-proces-
sor and cause application sputtering
by multitasking, it doesn’t occur very
often on a two-CPU machine. The clos-
est you can come to such effortless
multitasking on a single-proc box is
with Intel’s Hyper-Threading, which
intelligently distributes the workload
of a single CPU for a similarly smooth
user experience.So should you invest in an extra
CPU? If you’re primarily a gamer
and your application work is limited
to MP3 encoding, web browsing,
and Microsoft Word , the money and
power you’ll spend isn’t worth it.
Plus, next-gen features such as DDR2,
PCI Express, faster busses, and newer
CPUs will debut on single-processor
mobos. But, if the applications you
use are tailored to use more than one
CPU and you’re getting paid by the
job, than the second proc will pay for
itself in no time.CPU PERFORMANCE TWO OPTERON 248S ONE OPTERON 248
Premiere Pro (sec)^665^741
Photoshop 7 (sec) 260 277
Quake III Arena (fps)^275^260
PCMark 2004 CPU 5,223 4,
Mathematica (sec) 558 558
LightWave 3D 7.5c (sec) 52.8 97.
SYSmark 2004 207 166
Best scores are bolded.The test: If a 3.2GHz CPU cooled
to minus-20 degrees Celsius can be
overclocked to 3.8GHz, what happens if
you make it even cooler, say minus-
C? Do the limits of overclocking scale
with colder temperatures?The results: OK, we admit it—the Lab
is outfitted to handle many scenarios,
but cooling a CPU to minus-100 is
not one of them. So we turned to the
CPU makers themselves. While neither
AMD nor Intel wanted to disclose a
whole lot of details, we did get enough
information to answer the question.
AMD’s position is that there’s simply no
guarantee you’ll gain more clock speed
as you incrementally cool your CPU; thecompany also notes that performance
isn’t measured in just raw megahertz.
Intel was a little more forthcoming,
saying you can get a near linear
scaling of speeds with temperature.
It’s just that getting there is the
problem. Consumer CPUs aren’t
rated for extreme low temperatures
and the problems they can cause,
such as condensation. In fact, Intel
says you’re only supposed to take its
consumer procs to 5 degrees Celcius,
or 41 degrees Fahrenheit. Any lower
and they’re no longer guaranteed to
work. Intel does make CPUs for colder
environments, but only for specially
contracted purposes (like, say, the Ice
Station Zebra Lab).HOW HIGH CAN YOU OVERCLOCK A CPU?