Nehalem workstations: A new era in performance

Last May, InfoWorld presented a comparative roundup of workstations built on the then-new quad-core processors. In that review, I examined an entry-level machine, two midranges, and a high-end system. While impressed by their muscle, I still felt the need to explain how those workstations were a category separate from high-end desktop systems. The Nehalem workstations I examine this year, however, require no such explanation. They move the flag forward so far that few people would consider purchasing them for standard business applications, where a good desktop or laptop would be sufficient.

In this review, I evaluate three entry-level systems (one each from Dell, HP, and Lenovo) and two midrange to high-end systems (from HP and Dell). In an ideal world, it would have been fun to allow the vendors to send their biggest, fastest system and throw those up against each other to see what shakes out. However, top-end workstations today can hold 192GB of RAM, which alone can push system costs into the multiple tens of thousands of dollars. So we settled for high-end workstations under $9,000. This left unexplored only the super-high-end market, which is dominated by specialty applications and narrow industry niches.

[ Compare the Dell, HP, and Lenovo workstations on features. Compare their performance benchmark results, power consumption, and scorecards. ]

Why Nehalem matters Intel's Nehalem processors represent a truly new generation in the storied x86 processor history. Their release adds so many new features to the processor family that it appears almost unrecognizable. The key new elements are a built-in memory controller on each chip and high-speed interconnect between processors and peripherals. The interconnect, called QPI (QuickPath Interconnect), replaces the long-maligned FSB (front-side bus) that Intel chips were known for, while providing a superset of its functionality. QPI and on-chip memory controllers are both ideas initially implemented for x86 chips by AMD. In this first release, Intel has clearly refined the implementation. The result of both technologies is consistently greater levels of memory transfer than could be attained previously. (As shown in the accompanying benchmark table, the slowest system we review here has memory bandwidth that's twice that of the fastest system a year ago -- even though memory latency has decreased by only around 20 percent.)

In addition to these advances, Nehalem sports two important changes. First, the cache architecture has been moved to a three-tier system from the previous two tiers. The outermost, Level 3 (L3) cache is a stout 8MB shared by all four cores. When fewer cores are busy, the remaining cores get access to more of the cache. Each core can actually run two threads at once. This SMT (simultaneous multithreading) is a redux of Intel's earlier Hyper-Threading technology, although it scales better on Nehalem than in its original implementation. Hyper-Threading means that eight threads can run at once on a single processor -- that's a lot of instructions in flight at any given moment.

[ If you're unable to view the tables and images in this article, please click here. ]

The second important change to note is a Turbo mode that kicks in automatically when some cores are unused or underused. Their resources, including power, are contributed to the work of busy cores and can accelerate their performance by 5 to 10 percent, depending on the processor.

Given these numerous improvements, it's no wonder that Intel and its OEM partners promise a massive performance boost over the previous generation of Xeon processors.

Let's see how much more.

Entry-level workstations Workstations are generally divided into three market segments: entry level, midrange, and high end. Each segment outsells its higher-performance brethren, with the entry-level models hugely dominant in terms of numbers shipped. The entry-level models are typically single-processor systems, with fast graphics, a large RAM complement, and decent expandability. For this review, I look at entry-level models from Dell, HP, and Lenovo. Lenovo is the Chinese-owned company that bought IBM's PC and workstation business in late 2004. Last year, it began shipping its new line of workstations, although not in time for our May 2008 roundup. This year, the company provides a machine that does very well compared with its established rivals.

In advance of testing, InfoWorld provided all vendors with a complete set of benchmarks to be used, the criteria for evaluation with the respective weightings, and very few requirements for the systems. Entry-level systems had three requirements: a 2.93GHz Nehalem processor, Windows XP, and a price tag of under $6,000. As we indicated, this was an opportunity for them to send the fastest possible configuration they could put together that fit under the dollar cap. As it turned out, all systems sent in cost less than $4,000 -- they truly represent the value end of the market. I examined the Dell Precision T3500 model, the HP Z400, and the Lenovo ThinkStation S20.

[ Compare the Dell, HP, and Lenovo workstations on features. Compare their performance benchmark results, power consumption, and scorecards. ]

Of these three systems, I was particularly impressed by the Dell T3500, which won on all the performance benchmarks and had the lowest price. When compared with the midrange system from Dell that I examined last year, this year's entry-level T3500 creams it in every aspect except power consumption; the T3500 runs about 15 percent hotter at rest. My biggest complaint about the Dell is the difficult-to-access chassis -- upgrades are a pain. The system is also unaccountably heavy, weighing 10 pounds more than the lightest machine in this category. If you don't plan to upgrade your system (true of the majority of customers, according to all three vendors), then these concerns are not terribly important and Dell will give you a very fine system for an excellent price.

The Lenovo workstation performs neck and neck with the Dell, aside from the hard disk. The Dell T3500 comes with a high-speed two-disk RAID 0 configuration, whereas the Lenovo comes with a run-of-the-mill stand-alone disk. Lenovo does offer the striped RAID option, but this would require an additional cost over the price cited. Among several things Lenovo did particularly well is the design of its case. Lenovo and HP have both brought innovations to the case design. Lenovo's innovation is a large front handle by which it can easily be picked up and moved -- a possibility made real by its low weight. At 49 pounds, the Lenovo is the lightest system reviewed here.

Inside the case, the Lenovo's layout is conspicuously clean and free of clutter. A user could identify components and install upgrades with a minimum of fuss. This is also true of the HP Z400. In addition, the Lenovo was the most expandable of the entry-level systems, with -- count 'em! -- 10 external USB ports, six audio jacks, three special-purpose jacks, and a 20-in-1 card reader. Its only negative in terms of expandability is five PCI slots versus the six found in each of its competitors.

The HP Z400 is a solid system whose performance was hurt by the company's choice of an inferior graphics adapter. While the prices of the Dell and Lenovo systems included an Nvidia Quadro FX4800 with 1.5GB of video RAM, HP could deliver only the FX3800 with 500MB less memory for the same price. As a result, the HP Z400's performance numbers suffered, and its value score decreased commensurately. In terms of expandability, the HP is on a par with its competitors in most aspects, except for two categories: It offers only four DIMM slots for RAM (as opposed to six for Dell and Lenovo), and its power supply has the least capacity.

In summary, if your only criteria are price and performance, the Dell Precision T3500 is the right entry-level system for you. However, the highest overall rating for entry-level system goes to the Lenovo ThinkStation S20 due to comparable performance, better expandability, and greater usability. Either system will provide satisfaction. The HP workstation, in counterpoint, needs some work. At these prices, HP cannot ship a graphics card so distinctly secondary in performance. Until HP can resolve that issue and expand its DIMM slot count to six, it is unlikely to be the first choice of buyers in this market segment.

High-end workstations For the high-end systems, InfoWorld asked the vendors to provide systems meeting only two requirements: Windows x64 and a retail price tag of less than $9,000. Again, the vendors were given the benchmarks and scoring criteria and told to send the best system that fit the parameters.

Lenovo could not participate because it could not get us its dual-processor system in time. (The company was just about to debut its high-end dual-processor system, the ThinkStation D20, which is now available and should be included in any comparison by readers.) Dell sent us another fast system, but HP, unfortunately, sent a system configured well past the dollar cap that was agreed to. Because the item that pushed it past this barrier was substantially more RAM, we decided to give it the same RAM benchmark score attained by the Dell system. (Our first option, to remove RAM until we got under $9,000, became infeasible due to the HP workstation's RAM configuration. Either HP or Dell would have been unfairly penalized.) However, for all other benchmarks and criteria, we reviewed the system as shipped.

[ Compare the Dell, HP, and Lenovo workstations on features. Compare their performance benchmark results, power consumption, and scorecards. ]

Both Dell and HP submitted dual-processor configurations based on the quad-core Intel Xeon 5580 model that runs at 3.2GHz. The Xeon 5580 has all the goodies of the Nehalem described earlier, but runs faster than any model currently available. With two of these processors screaming at 100 percent utilization, these workstations consume more than 400 watts of power, and with that power comes heat. These workstations have a lot more fans and generate more noise than the entry-level systems, which were all whisper-quiet. These systems make their presence known -- although the noise is not disturbing at low workloads.

Looking at the features and benchmarks, it is apparent that Dell is once again the price-performance leader. It offers more graphics power than HP, which unaccountably used the same midrange graphics board it shipped us in the entry-level system. Disk speed is faster on the HP, about double the rate, but for our review, disk drive speed is for information only -- it does not enter into performance ratings, as disks are viewed as peripherals separate from the machine itself. As to the disk performance, both systems used a RAID 0 configuration with data striping. Dell's choice of slower disks accounts for most of the difference from HP's Z800 number. As explained earlier, the memory bandwidth for both workstations is perforce the same.

Dell's other advantages are that the T5500 is more energy efficient and weighs less than the HP system. In addition, it uses a smaller form factor -- identical in size to the T3500. The smaller chassis makes the insides of the T5500 a dense jumble of wires, daughtercards, risers, and other components. It also limits expandability to four drives and a maximum of nine DIMMs (of which three are on a riser card). For purchasers of this system, it will be important to choose the final configuration early, as upgrading the system in-house will be an unpleasant chore.

Putting aside the performance gap -- which you can erase by purchasing a higher-end video card from HP -- the HP is a superior all-around workstation. It contains numerous features that show an appreciation of user needs. The case, for example, has two large, built-in handles (front and back) to facilitate moves. When you open the case, everything is tidily hidden behind snap-out covers and cowlings. These covers have colored tabs to show where to press or pull to remove them. All components, including the power supply, can be removed and reassembled using only these tabs as guides. No screwdriver is needed. Below these guides, there is room for 12 DIMMs and six hard drives, four of which use snap-out trays. The 1100W power supply, which snaps out easily, provides plenty of power for this expansion.

The outside rear panel on the Z800 sports two GbE ports (all the other workstations have only one), of which one can support ASF (alert standard format) for remote manageability. In a nice touch, the sides are molded so that plugging network cables into the Ethernet jacks does not pinch fingers. With Dell's system, by contrast, unplugging an Ethernet cable can be a delicate procedure due to space constraints. For all this goodness, the HP system is 12 pounds heavier than the Dell T5500, and alas, it makes more noise, especially during disk activity.

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