by Michael Desmond
Two heads are better than one. That's the mantra preached by processor
makers Intel and Advanced Micro Devices entering 2006. More and more
CPUs found in mainstream desktop PCs -- and even notebooks -- are using
so-called dual-core designs, which essentially bundle two CPUs into a
single square of silicon.
But despite the dual-core religion, PC makers aren't necessarily
harping on the new technology. You could buy a system today and not
even know you were getting a two-headed monster under the hood. So
what is it? And why the double dip?
Around 2003 or so, the Intels and Dells of the world began to notice a
disturbing trend. Ever-faster CPUs were running so hot that they made
it difficult to ramp up performance. Industry watchers began talking
seriously about water-cooled systems, even as Intel struggled to churn
out high-end processors. CPU makers simply could not count on
aggressive clock rate increases to produce faster performance.
Enter dual-core CPUs such as the AMD Athlon 64 X2 and Intel Pentium D.
These processors incorporate two CPU cores to bring more gray matter to bear
on computing tasks. More important, they work together to deliver excellent
performance at lower clock rates than their single-core counterparts. The
result: cooler operation and less stress on minute silicon transistors,
which is critical to producing affordable CPUs.
You might expect a dual-core CPU to be twice as fast as a single-core
model running at the same clock speed, but you'd be wrong. A lot of issues
conspire to dilute the performance impact. First, dual-core CPUs can only
work their magic when there is more than one discrete set of tasks to work
on -- known as a "thread" in computing parlance. A single-threaded application
running on a dual-core CPU simply will not benefit from that second core.
Second, any time you try to share work between cores, there's overhead
involved. Depending on the nature of the task, you can expect that
adding a second core will boost performance by up to 70 percent over a
single-core CPU. But again, because dual-core CPUs run at lower clock
rates, the advantage over competing single-core processors is slim. PC
World benchmark tests show that today's top-end single-core CPUs
remain competitive with top dual-core CPUs.
Software Goes Multicore
Still, there are plenty of situations where dual-core CPUs can work
their magic, says industry analyst Nathan Brookwood. Business users,
for instance, typically have several programs open at once. Dual-core
CPUs can help speed things up when you are doing many things at the
same time, such as working on a document while loading a page in your
Web browser and listening to music on a media player.
Most important, more and more software is being tuned with dual-core
processors in mind. Brookwood singles out game vendors and
graphics-card companies as two groups that have aggressively adopted
multithreaded architectures to tap dual-core systems. "Even if the
game is single-threaded, all the graphics and 3D [drivers] are
multithreaded," says Brookwood.
Multithreaded code is already present in many media-creation
applications, such as Adobe Photoshop and Premier. You can expect
multithreading to become more pervasive as software vendors seek to
cater to a large installed base of dual-core CPUs. The result: Buying
a dual-core system today will help you take advantage of coming
performance improvements tomorrow.
But all dual-core processors are not created equal. Chris Connelly,
marketing director for PC maker GamePC, says AMD has enjoyed a
significant lead in the performance of its dual-core offerings
compared to those of the Pentium D. He singles out system offerings
like the GamePC Disruptor-SLI series, which incorporates top-end
technology for high-end gaming and desktop applications. The
Disruptor-SLI family is based on AMD Athlon 64 X2 processors.
"The biggest complaints about Intel's dual-core products were that the
chip used too much power, creating too much heat in the process, and
the chips themselves did not perform as well as many expected, given
their high clock rates," says Connelly.
All that may be changing. Brookwood says that next-generation desktop
chips from Intel will be much more efficient, delivering more
performance at lower clock rates than current offerings.
"I think the competitive situation between Intel and AMD will grow
tighter, and that always benefits buyers," says Brookwood, adding that
once Intel rolls out its dual-core desktop processor, code-named
Conroe, in the second half of 2006, "that's going to make Intel much
more competitive with AMD."
The tight competition should help make multicore systems a staple on
the market, says Connelly. GamePC expects 90 percent to 95 percent of
the systems it sells at the end of the year to be multicore.
Dual-core CPUs may be a no-brainer for all but low-end systems, but
tough decisions still await buyers. For instance, 64-bit CPUs are
already making their mark in the consumer market, led by AMD's
successful Athlon 64 line. And Brookwood says that anyone
contemplating the next version of Windows -- called Windows Vista --
should be thinking about a 64-bit CPU.
"Vista will certainly take advantage of 64-bit code in ways that
Windows XP does not," says Brookwood. "The belief is that 32-bit programs
running on Windows Vista won't run as fast as their 64-bit equivalents."
There are real implications. A 64-bit version of Adobe Premiere, for
instance, might be able to render a large video several hours faster
than the 32-bit version of the same program. "You may very well want a
64-bit computer," Brookwood says.
What's more, Brookwood says that quad-core processors are in the
works. The additional cores will further scale performance, enabling
processors to achieve new levels of performance without pushing heat
output to untenable levels. Recent Intel road map information,
published by Tom's Hardware, shows quad-core and even eight-core CPU
platforms emerging in the 2008 time frame.
Is the single-core processor finished? Not by a long shot, says
"For people who are doing the Web over even a moderate broadband link
-- e-mail, word processing, spreadsheets, heavy-duty gaming like
Solitaire," he jokes, "they don't need a lot of processing power to do
that. [Low-end processors] will stay single-core because it's cheaper
to make a single-core processor than a dual-core processor."
Michael Desmond writes from his home in Vermont. He wonders if CPU
makers will take multicore marketing to the silly extremes of companies like
Schick, which touts a four-blade men's razor.
Copyright 2005 Yahoo/Tech Tuesday