Dell Carves Out Energy-Efficient PowerEdge Server Line

Published: December 6, 2006

by Timothy Prickett Morgan

Hoping to capitalize on the craze for energy-efficient machinery, server maker Dell yesterday rolled out a new line of PowerEdge Energy Smart servers, which use low-powered processors, storage, and power supplies. The machines also have a little extra engineering in them to make them use less electricity and therefore require less cooling, and the net effect is that an Energy Smart machine can deliver 25 percent better performance per watt than a regular PowerEdge box.

Power and cooling issues do not just affect the data center, of course. For instance, Dell says that its new OptiPlex 745 personal computer can use 70 percent less energy than previous generations of its business PCs, and that if the energy efficiency settings on this PC were applied to all Dell desktops, then enough electricity would be saved to avoid pumping 12.5 million tons of carbon dioxide emissions into the environment. By Dell's math, this would be equivalent to taking 2.5 million cars off the road. Businesses would also save about $1.6 billion in operating costs associated with powering up those PCs and cooling their offices as these machines generate heat.

But because of the density of computing components in the data center--which has been exacerbated by the move toward higher-performing and more compact form factors for servers and storage--Dell's announcement yesterday is taking on the data center. And, the Energy Smart PowerEdge boxes announced yesterday--which start shipping tomorrow--are variants of the two most popular Xeon-based models in the ninth generation of PowerEdge boxes.

Specifically, there are two Energy Smart machines, which are variants of the two-socket, 1U form factor PowerEdge 1950 and the two-socket, 2U form factor PowerEdge 2950. These machines were pre-announced ahead of Intel's dual-core "Woodcrest" Xeon 5100 launch back in June. And thanks to the Woodcrest chips, the ninth generation PowerEdge boxes offer performance and performance per watt that is comparable to that offered by designs that use the X64-compatible Opteron processors from Advanced Micro Devices. AMD has made lots of hay with the power-efficient Athlon and Opteron processors, but Intel has largely caught up. Still, some customers need lower power and thermals than the standard Xeon and Opteron parts can bring, which is why Dell is carving out a niche Energy Smart product line.

The Energy Smart PowerEdge 1950 and 2950 models both use a low-voltage Woodcrest part, the Xeon 5148, which has a 40-watt thermal design point (TDP) rather than the 65-watt or 80-watt TDPs of other Xeon parts. The Xeon 5148 clocks at 2.33 GHz, compared to 3 GHz for the top-end Xeon 5160. So customers have to sacrifice about 20 percent of the processor's raw performance to cut the thermals in half. These servers will also only be available with 2.5-inch SAS disk drives, rather than 3.5-inch SCSI or SATA-II drives, which burn more energy and which also spin a bit faster. There is a tradeoff between energy and computing performance, and there is no getting around it. Jay Parker, director of PowerEdge servers in Dell's Product Group, says that the Energy Smart machines also include other optimizations to reduce power consumption, such as using more efficient power supplies, which can run at as high as 83 percent efficiency in the Energy Smart boxes. The machines also have what Dell calls low flow fan technology, which is a fancy way of saying that if the fans do not need to be whirring because a machine is not doing a lot of work, they automatically slow down. Dell has made other tweaks in the BIOS of these servers so Demand-Based Switching, which lets the clock speed of a Woodcrest chip float up and down with workload demands, is enabled; Dell has similarly implemented circuitry that allows memory speeds to be moved up and down as needed, which also saves energy. When you add it all up, these changes in the server result in that 25 percent better performance per watt.

The next effect is that customers can lower the power and cooling requirements in their data centers by moving to such machines, or they can add more machines to the data center without consuming more power and requiring more cooling.

The PowerEdge Energy Smart 1950 costs $2,449 in a base configuration, while the Energy Smart 2950 costs $2,619 in a base setup. Parker says that this is a $100 premium over similarly configured plain vanilla PowerEdge 1950 and 2950 machines--which already support the Xeon 5148 chip, by the way. Parker is pretty sure that companies will pay that $100 premium, since installing such a machine to replace a regular PowerEdge box using Woodcrest chips would save a company about $200 a year, based on an average of prevailing electricity costs today.

What Dell did not do yesterday, by the way, was flesh out its Opteron-based PowerEdge server line with the HE and EE variants of the latest Opteron Rev F chips, which it certainly could have done. The HE, short for Highly Efficient, and EE, short for Extremely Efficient, Opteron parts play the same games with voltages to reduce the thermals of the chip. Regular Opterons run at 95 watts, while the HE parts run at the same clock speed (but not the top-end speed) and burn only 68 watts; the EE parts, which AMD has had difficulty bringing to market, run at a lower clock speed still, but have a 35 watt TDP. It is important to note that the Opteron chips include the memory controller, while the Intel chips do not. So the TDP-to-TDP comparison is not exactly fair to AMD.

While Dell did not launch Opteron-based Energy Smart servers yesterday, it undoubtedly will, even though Parker hedged a little.

"Certainly, I believe that this is a likely future direction for 2007," he explained. "But the PowerEdge 1950 and 2950 are our highest volume servers, and we thought that it was important to get these Energy Smart versions to market first to have the greatest, immediate impact. As our AMD line expands over time, you can expect Energy Smart products here as well."

It is hard to say when tower-based computers will get the Energy Smart approach, since these are departmental boxes at big companies or the only machine at smaller ones. Energy consumption, heat, and cooling are not issues for small businesses the way they are for large enterprises. But, every little bit will help.

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