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.
Future-Proofing
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 Brookwood.
"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