44 MA XIMUMPC JUNE 2005
Q
I’ve heard the hype about
dual-core processors, but
what makes them different
from other gimmicks—such as
a faster front-side bus or a larger CPU
cache—that have been used in the past
to convince me to upgrade?A
Unlike some of the fancy-pants
marketing-driven crap we’ve
been fed over the years, dual
core is a major step forward
for PC computing. It’s basically a two-
fer—you get two execution, or processor,
cores in a single CPU package, and each
core can crunch data independent of the
other. Those who have used dual-pro-
cessor machines can tell you just how
“smooth” having two execution cores
can make your computing experience,
even under heavy processor loads.
While your single-proc rig normally
wouldn’t have any clock cycles to spare
during a strenuous DVD rip and encode,
a dual-core PC merrily crunches your
video while you browse the net or edit
huge WAV files at the same time.Q
Sounds good, but is it any
more effective at multitask-
ing than my Pentium 4 with
Hyper-Threading?A
You betcha. Hyper-Threading is
Intel’s gallant strategy to make
more efficient use of a single
execution core. Because com-
mon computing tasks don’t use 100 per-
cent of a CPU’s resources, Hyper-Thread-
ing splits the physical CPU core into two
virtual cores, which al-
lows you to usedifferent portions
of the CPU core for
different tasks at the
same time. Compress-
ing your digital audio
to MP3 occupies the
floating-point resources
of the processor, while
tasks that aren’t floating-
point intensive (say, word
processing or browsing the
Internet) can avail them-
selves of the chip’s other
resources. Hyper-Threading
has proved to be valuable for
people who do multiple things
at once, but it doesn’t work
well when you present it with two apps
that function similarly—floating-point
operations, for example. In the end,
you’re still trying to divvy up the physi-
cal resources of a single processor. Be-
cause dual core gives you two full CPU
cores (each with its own cache, in some
configurations), you can breeze through
two floating-point intensive apps at
once, something that would strangle a
mere Hyper-Threading processor.Q
If I’m getting two CPUs, does
that mean I’ll get double the
performance?A
Not in the near future, unfor-
tunately. The overwhelming
majority of applications and
games available today aren’t
optimized to exploit the advantages
of dual-core processors. In order for
software to get the best performance
out of a dual-core or multi-chip proces-
sor (or even a dual-processor system,
for that matter), the program must
spawn multiple threads that can
be farmed out to each processor
core. Today’s applications and
games rarely create enough
threads to use dual cores
effectively; so don’t
expect a big boost
in performance from
your current Divx
encoder or Unreal -
engine game.Q
So I won’t see any tangible
performance differences with
a dual-core processor unless
my apps are pervasively multi-
threaded?A
You won’t with individual
applications, but you’ll still
reap significant performance
benefits if you run more than
one app simultaneously. Try to encode
a video clip to Divx and batch-process a
stack of MP3s on your single-processor
PC, and you’ll go gray waiting for both
tasks to complete. Try the same maneu-
ver with a dual-core proc, and each app
should run almost as fast as it would
on a comparable single-processor box.
That’s the “smoothness” that dual-pro-
cessor users have enjoyed for years, but
now AMD and Intel are offering the same
benefits to everyone—with dual-core
CPUs that won’t cost much more than
single-core processors. It’s even more of
a deal when you consider that to make
a dual-core processor, AMD and Intel
use twice as much silicon as they do
when making a single-core chip. And,
of course, once applications and games
are updated to better take advantage of
dual-core processors, you’ll get wildly
improved performance and fewer cof-
fee breaks waiting for multiple tasks to
finish. Depending on the app, you could
reap a 100-percent performance boost,
which is a hell of a lot more than you
would have gained with an extra helping
of L2 cache.different portions
of the CPU core for
different tasks at the
same time. Compress-
ing your digital audio
to MP3 occupies the
floating-point resources
of the processor, while
tasks that aren’t floating-
point intensive (say, word
processing or browsing the
Internet) can avail them-
selves of the chip’s other
resources. Hyper-Threading
has proved to be valuable for
people who do multiple things
at once, but it doesn’t work
well when you present it with two apps
that function similarly—floating-point
operations, for example. In the end,
you’re still trying to divvy up the physi-Q
So I won’t see any tangibleing splits the physical CPU core into two
virtual cores, which al-
lows you to useof dual-core processors. In order for
software to get the best performance
out of a dual-core or multi-chip proces-
sor (or even a dual-processor system,
for that matter), the program must
spawn multiple threads that can
be farmed out to each processor
core. Today’s applications and
games rarely create enough
threads to use dual cores
effectively; so don’t
expect a big boost
in performance fromAMD’s dual-core Athlon
64 X2 clocks in at 2.2GHz and
has 1MB of L2 cache per core.The dual-core Pentium Extreme
Edition clocks in at 3.2GHz and
features support for Hyper-
Threading.