Two cores better than one?

Dual-core processing has been the Next Big Thing in computing since Advanced Micro Devices Inc. of Sunnyvale, Calif., and Intel Corp. began rolling out new chips earlier this year. It's been hailed as an industry-altering marvel'and PC makers' best chance to improve system performance without ratcheting up clock speeds to the point where a computer could heat a small room.Depending on how you use a PC, this may actually be true.Quick recap: Dual-core processors are es-sentially two CPUs in one, each core with its own memory cache, and each capable of running applications independently of the other. Neither AMD nor Intel invented dual-core chips. IBM Corp. and Sun Microsystems Inc. developed dual-core processors years ago, but they weren't based on the x86 standard. With most of today's software, which isn't designed to support so-called symmetric multiprocessing, a second core kicks in when the first core can't handle the workload. (When software and an operating system are written for SMP, a single application can be broken down into threads that can be processed by both cores.)The GCN Lab got its hands on four new dual-core desktops from leading PC vendors Alienware Corp., Dell Corp., Gateway Inc. and Hewlett-Packard Co. Alienware's system featured the AMD Opteron 275, while the other three used dual-core chips from Intel. Once we were able to play with them, it was clear they were fast, but dual-core isn't just about speed. So we had to adjust how we tested.To evaluate a central premise of dual-core processing, we reprogrammed the GCN Alterion application benchmarks to run two instances of the suite at the same time. This means that every time we kicked off the test script, each system was simultaneously running two instances of Adobe Photoshop, then two instances of Microsoft Excel and so on through our application-based benchmark. Each script produced its own Alterion score, which we report separately and averaged together.As a control, we tried to run the new dual-script benchmarks on several single-core systems. In isolated cases where the single-core PCs didn't crash under the strain (and most did), scores were generally 4,000 to 5,000 points lower than those of dual-core systems, proving what you already know: It's hard to run multiple applications on today's Microsoft Windows PCs.When the dust settled, dual scripts running on dual-core PCs produced good scores across all the systems in our review. No, these machines didn't score uniformly higher than the top single-core systems we've tested, but they performed at least as fast as most single-core PCs while handling twice the workload. (We also tested all dual-core machines with a single instance of the Alterion benchmark and the scores came out equal to the average of the two simultaneous scripts.)In the case of the Dell OptiPlex GX620 MT, one of the two scripts actually produced the highest Alterion benchmark score we've ever seen. The other did not, however, so we're not ready to call it the fastest system we've tested. In fact, both the Dell and the Gateway E-6500D produced one score that was significantly higher than the other. This indicates that the cores in those systems were configured to hand off processing chores differently than in systems that turned in two similar scores. Although this is not something the user can set, it appears that certain dual-core systems assign priorities to their chips dynamically based on the task at hand. We performed multiple benchmark tests and got the same results. Bottom line: The average of the two scores best reflects each system's performance in daily applications.Of course, one of the big questions we asked ourselves was which would perform better, AMD or Intel? On this the jury is still out. The two cores in our Alienware test system ran at 2.2 GHz, as opposed to 2.8 GHz and 3.2 GHz in the Intel-based systems. Although Alienware's score was predictably lower, it wasn't drastically so. In fact, as an average of both scripts, Alienware's Alterion score was nearly identical to that of the Gateway E-6500D.Granted, the Alienware MJ-12 7550a came with a higher-end video card with more graphics memory, but we wouldn't hesitate to recommend AMD-based dual-core systems.Overall, though, the best news may be that dual-core processing doesn't necessarily mean sky-high system costs. Our favorite PC, the HP Compaq dc7600, ran like a champ, came with all the features you'd expect in a desktop and only cost $1,029 (without the monitor).Should you buy one? As always, it depends on what you'll use the PC for. For many, single-core systems are just fine. But if you're in the middle of a large-scale refresh, economical dual-core PCs could offer important future-proofing in the event more software is tuned to take better advantage of the technology. Loaded with features, maximum expandability Prohibitively expensive B A+ B-The MJ-12 7550a from Alienware is more workstation than desktop PC. Nearly everything about this computer is top of the line, but that of course means the price is also on the high end.Even the motherboard on this system is about the best you can get. If you find that your multitasking is so great that you tax the limits of a dual-core processor, the Tyan Thunder motherboard has a socket ready for a whole second CPU. Its eight (yes, eight) memory slots will allow the user to keep up with software demands for quite some time. And the card expansion slots are sufficient for almost any needs.You may think that 320GB of hard drive space in a pair of 160GB serial ATA drives is far more than any user would need, but history has shown that storage needs increase at an alarming rate.[IMGCAP(2)]The Nvidia Quadro series of video cards are about the best ones that money can buy. Even though it takes up two whole PCI Express slots (one just for the cooling system), it's worth it for any job that is graphically intensive, such as CAD work, video editing or scientific applications.Even the power supply is top of the line, with plenty of wattage and clean bundling of power cords. About the only thing this system doesn't include is a parallel printer port, which is a consideration only if you don't have a USB printer.With a 2.2-GHz AMD Opteron 275 processor, the 7550a performed adequately, pulling down an average benchmark score of 7,560. Though quite good, it was less impressive than other systems tested here. But it's still better than several single-core systems we've seen this year, including a 3.4-GHz Intel Xeon-based workstation.Ultimately, while the components in this system are worth a little extra money, we feel its $4,666 price tag is still a bit steep, especially if you're looking for multiple systems. However, specialty users, such as those at NASA or in the intelligence community with high-end workstation needs, may see things differently.Alienware Corp., Miami, 800-254-3692, Fastest performance Minimal expandability A B- B+Dell's OptiPlex GX620 is all about processing power. But if expandability is a concern, this system may run you into some roadblocks. Available expansion slots are few, so keep that in mind if you plan to upgrade.While the GX620 boasts eight USB ports, the absence of PS/2 keyboard and mouse sockets means two of those USB ports are earmarked out of the box. Call it six USB ports, which should still be plenty.The 80GB hard drive should be sufficient for most users, but these days it would be easy to fill up. You may want to opt for a larger drive, especially considering how cheap storage is today.What may actually prove a problem down the road, especially if you add to the system, is the power supply. The 305-watt supply that comes with the GX620 puts out just enough power to drive what comes with the system. However, if you put in a second drive or some other add-on, it might overload the system. And, unfortunately, Dell does not provide the option to upgrade the wattage of the power supply.Where the GX620 excels is raw horsepower. The 3.2-GHz Pentium D 840 is the fastest dual-core desktop processor Intel currently offers. With help from the bundled ATI Radeon X600 Pro video controller, the GX620's average Alterion benchmark score of 8,896 exceeded every other system in our roundup. This level of performance should be more than enough to run several applications at once with little noticeable slowdown.The top-of-the-line processor contributes to a list price of $1,677, which seems high considering other components are less than cutting edge. Dell says government users can get the GX620 for a more reasonable $1,495.The OptiPlex GX620 would be good for someone who wants to run several instances of typical office-related programs, but has no need to expand beyond what comes out of the box.Dell Inc., Round Rock, Texas, 800-388-8542, [IMGCAP(3)] Integrated surround sound Processor power B B+ A-Gateway's E-6500D is well suited to multimedia applications, despite the fact it isn't one of the fastest dual-core systems we tested.The bundled Nvidia GeForce 6600 graphics card is one of the better mid- to high-end cards available and is perfectly suited for displaying video, 3-D or other graphically intensive output.And the E-6500D is the only system we saw that came with integrated high-definition surround sound.How that factors into daily agency use isn't clear, but it could have specialized application to presentations, training or other chores.Three FireWire and seven USB ports allow for a variety of input/output devices. Plus our test system had two 160GB hard drives in a RAID 0 configuration, ample storage space for multimedia and other content.The motherboard has three open full-length PCI slots and one available PCI Express slot, so the options for expansion are many. Unfortunately, with a 305-watt power supply, you would have to select add-ons carefully. Gateway does offer a larger power supply.With its 2.8-GHz Intel Pentium D 820 processor and Nvidia controller, the E-6500D generated an average benchmark score of 7,561, which, while respectable, is lower than that of HP's dual-core system based on the same processor (see below). Interestingly, that score is also lower than the single-core, 2.8-GHz Pentium 4-based E-4300 we reviewed in July. And that system ran Intel's sluggish GMA 900 integrated graphics processor, which leads us to believe that Gateway has some room to improve the performance of the E-6500D in the coming months.The Gateway E-6500D's $1,456 list price is fairly reasonable and reflects the system's massive storage capacity, but we wouldn't call it a bargain. Overall, the system is fairly no-frills but with ample possibilities. It would be perfect for users on the lookout for multimedia perks.Gateway Inc., Irvine, Calif., 800-846-2000, www.gateway.com Hewlett-Packard Compaq dc7600 Great price, strong security Expansion limitations A- B A+The Compaq dc7600's enhanced security features make it one of the most secure systems available. And the price makes it a steal.Hewlett-Packard uses an integrated TPM-compliant security chip, which provides hardware encryption for an additional layer of security. This encryption can be used to block off certain partitions on the hard drive, or even prevent the entire system from booting up unless the proper password is entered.The DDR2 667-MHz memory is about the fastest around, and it proves it. With an average benchmark score of 8,105, the dc7600 was significantly faster than the Gateway E-6500D, which had the same processor but slower memory.Unfortunately, when vendors add features, they usually cut other corners to keep the price down, and the dc7600 is no exception. The ATI Radeon x300 SE video card and 128MB of memory are less than optimal and could present a problem with some higher-end software. Also, with only 80GB of hard drive space, storage limitations may be a problem down the road. And lastly, there are only two PCI slots left over inside the chassis, so expandability is a concern.Still, at a $1,029 list price, a lot is forgiven. For a system with the dc7600's configuration, this price is more than a little attractive and it's one of the main reasons we recommend this dual-core system over the others. If you're looking for good processing power and extra security at a very reasonable price, the dc7600 fits the bill.Hewlett-Packard Co., Palo Alto, Calif., 800-752-0900,