Crazy From the Heat

Hot-running PCs force Intel and AMD to dream up new ways--think dual core, 64-bit computing--to improve the performance of systems you'll buy in 2005.

Michael Desmond - Tuesday, April 19, 2005

Moore's Law is dead. Actually, let me rephrase that--Moore's Law is cooked. The idea that processor performance will double every 12 to 18 months was famously expressed by Intel cofounder Gordon Moore way back in 1965. Since then, we've seen eight presidents, three wars, the fall of the Soviet Union, and a Boston Red Sox World Series victory. Yeah, it's been a while.

Alas, all good things must come to an end. Three years ago, Intel touted a vision of Pentium 4 processors running at 10 GHz, but the architecture stalled before it could reach 4 GHz. The problem has been heat, as increasing clock speeds and transistor counts have turned central processing units into virtual furnaces. System makers have fought the good fight, bolting on more and larger heat sinks and cooling fans to push the hot air out of systems. Some high-end PC makers have gone so far as to market water-cooled computers. But the writing has been on the wall for well over a year: Cutting-edge CPUs run too hot to continue to keep pushing clock rates.

So why not buy a new PC today, since they currently go as fast as they ever will?

Hold the phone. That's only partially accurate. Intel-compatible computers will continue to get better, just not in the way you may be used to. Understanding how computer processors are evolving will help you make educated buying decisions.

Clock speeds may have hit a wall (have you noticed Intel and archrival Advanced Micro Devices no longer boast about gigahertz?), but tomorrow's computers will still handle your software better than today's. The party isn't over--it's just moved to another room.

Dual Core
Over the past couple weeks, Intel and AMD have introduced revolutionary dual-core processors that steal a page from the book of high-end workstations and servers to boost performance. With two CPUs built into one chip, every desktop--and even laptop--can multitask with aplomb. One CPU can tackle a video-compression routine while the other processes e-mail or a spreadsheet program. Intelligently designed software can even be broken into parts--called threads--that let both CPUs work on a single application.

In theory, dual-core CPUs could almost double performance, but the immediate gains won't approach that. To manage the pesky heat issue, AMD and Intel are introducing dual-core CPUs that run significantly slower than their single-core siblings. So while the fastest single-core Pentium 4 runs at 3.8 GHz, the dual-core Pentium D and Pentium Extreme Edition peak at 3.2 GHz. Two slower-running cores reduce heat and electrical stress while still increasing overall performance.

64-Bit Computing
Confused enough? There's more. New desktop and laptop PCs are beginning to incorporate CPUs capable of processing 64-bit software. As with the dual-core technology, 64-bit architectures come from the high-end server and workstation world, where the technology lets systems handle massive collections of data and extremely complex instructions. Chris Connolly, Web operations manager for PC maker Game PC, says the value of 64-bit processors remains years away.

"While 64-bit technology can be utilized today through Linux and Windows XP 64 Edition, 64-bit still isn't truly useful in today's desktop environment, and likely won't be for several years," Connolly says. "We don't expect to see huge performance gains when moving up to a 64-bit platform."

Today, 64-bit capability is a nice-to-have feature that might future-proof your PC when 64-bit consumer applications finally arrive two or three years down the road. More likely, though, you'll want to replace your aging PC later to make an effective jump to cutting-edge 64-bit applications.

With all the new processors and architectures, how is a buyer supposed to decide what will work best? Let's walk through the options. Keep in mind, by the time I finished talking to Intel and AMD for this story, both companies were jockeying to be the first to ship dual-core chips--and both did so last week. PC vendors are getting their hands on them as you read this.

High-Performance Gaming
AMD Athlon 64 FX-55: The Athlon 64 FX, a single-core speed beast, just got faster. It won't out-multitask the new dual-core CPUs, but for pure gaming, it remains AMD's king of the hill. Connolly says: "Intel's high-end Pentium 4 processors will best the FX-55 in some areas, but overall, the FX-55 takes the cake."

Intel Pentium Extreme Edition 840: Intel has gotten dual-core religion, and is touting the new Pentium Extreme Edition 840 as its gaming power house, with its 3.2 GHz clock and 1 MB of L2 cache per core. As game developers start to tune their software with multiple threads, expect the dual-core Extreme Edition to make gains. The dual-core Pentium D 840 is a more economical alternative.

High-Performance Media
AMD Athlon 64 X2 4800 Dual Core: Running at 2.4 GHz with 1 MB of cache per core, the top-end Athlon 64 X2 CPU should deliver breathtaking results in performance-intensive tasks like video compression, photo editing, and multitasking.

Intel Pentium Extreme Edition 840: Once again, the Pentium Extreme Edition 840 gets the nod. Extreme Edition processors' inclusion of Intel's Hyper Threading Technology turns the dual core into a virtual four-core processor--a real bonus for media environments that often present multiple threads and even applications.

Mainstream/Midrange
AMD Athlon 64 3500+, Athlon 64 X2 4200 Dual Core: In the Windows XP era, mainstream computing is all about multitasking. So the AMD Athlon 64 X2 4200 Dual Core processor is a natural fit. The question comes down to price: discounts on the existing AMD Athlon 64 3500+ could make this CPU too good a deal to pass up.

Intel Pentium 4 640/Pentium D 8xx: As with AMD, Intel's single- and dual-core offerings overlap in the midrange. Buyers can look to either the Intel Pentium 4 640 or the dual-core Pentium D 8xx line for systems that deliver impressive performance without breaking the bank. If you tend to run a lot of applications side by side, the Pentium D should offer a clear advantage.

Budget
AMD Sempron 3100+: The newest member of AMD's impressive low-end CPU line offers beefed-up features and compatibility with AMD's latest motherboard socket designs. Connolly also singles out the low-end, single-core Athlon 64 processors for budget systems.

Intel Celeron D 340: The Intel Celeron family got a critical boost with the enlarged 256KB cache and other enhancements in the Celeron D refresh. While you'll see a slight cost savings over Sempron CPUs, the top-end Celeron D 340 lags behind Sempron's finest in overall performance.

Mobile
AMD has launched a mobile crusade, introducing mobile-optimized versions of its Athlon 64 and Sempron processors. Most significant is the release of the new AMD Turion family. These mobile-dedicated processors come in two types--the performance-minded Turion ML and the power-savvy Turion MT. The Turion MT should, for the first time, give AMD a credible presence in the arena of thin and light notebooks.

Intel, meanwhile, continues to ply its successful Centrino architecture in the mobile space. Connolly singles out the Intel Pentium M 770 as "the best overall mobile chip on the market right now," with its "excellent performance, a good feature set, and unbeatable battery life." With a future mobile chip, code named Yonah, Intel expects to shrink the transistor size to enable lower power consumption and higher performance. A dual-core version of Yonah should ship in the first quarter of 2006.

It'll take a couple years before almost every PC becomes a two-headed monster, but in the meantime, shoppers must exercise a lot of caution to make sure they get the hardware they need. As the effort to increase clock rates becomes more difficult, the competitive battleground shifts to features and component integration--concepts that may introduce more confusion to an already confused audience.

"Both companies are slowing down and adding more features to their processors rather than just pumping up the clock speeds, which is proving to be good for the industry," Game PC's Connolly explains. "I think we will continue to see slow, steady gains in clock speed over time instead of the breakneck speeds we've seen in the past two years."

Michael Desmond is publishing director at Bock Interactive, a Web commerce solutions and consulting firm in Burlington, Vermont. He's written two books about PC hardware.