Some analysts agree. Although Opteron power totals are lower on paper, Thomas Weisel Partners, in a June 22 report, said it found in a test that two Opteron systems drew more power at the wall than an Intel Woodcrest machine. The two chip makers approaches differ in that Opteron includes a memory controller for DDR DRAM (double data rate dynamic RAM), while Woodcrest chips, like other Intel processors, use discrete controllers and FB-DIMMs (fully-buffered dual inline memory modules). FB-DIMMS use standard DDR2 but embed a buffer chip in each module to boost performance. FB-DIMMs thus use more powerroughly nine to 10 watts of powercompared with non-buffered DDR modules, which use about 4.5 watts.Tests by Tomas Weisel Partners shown in the report found than the Woodcrest system, an Intel Star Lake white box with a 3GHz Xeon 5160 and four 1GB FB-DIMMs, used less power than a Sun Microsystems SunFire x4200 with an Opteron 285 processor running at 2.6GHz and 4GB of DDR and a Monarch system, constructed from a Tyan Thunder K8S Pro motherboard, Opteron 285 and 4GB of RAM.When under load, running SunGuards Adaptive Analytics Application, the Woodcrest machine used 243 watts, 75 watts fewer than the Sun machines 318 watts, for one, the report said. Intel has conducted similar tests and trumpeted similar results. AMD isnt sitting idle, however. The chip maker plans to deliver a new version of its Opteron chip, which offers redesigned circuitry and a new DDR2 memory controller, in the third quarter. AMD says the combination will offer greater energy efficiency. Server makers and their customers are benefiting from the competition between the two chip makers. Dell server users can now order the PowerEdge 1950, 2950 and 2900 servers, and the 1955 blade systems, with Xeon 5100 chips. Dell later this year also will start shipping a four-way server powered by Opteron, the first AMD-based system from the company. HP in May introduced new and enhanced ProLiant servers using the Xeon 5100, and will start shipping those June 26. HP also has a full line of Opteron-based ProLiant systems. IBM is bringing its PowerExecutive technologywhich monitors the power usage in a server or group of serversto its System x and BladeCenter servers for free. The two-year-old technology will complement the power efficiency offered in Woodcrest, according to IBM officials. The company says the new systemsthe x3650, x3550 and x3400 and BladeCenter HS21will see up to a 163 percent performance increase over current servers. Gateway in the fall will offer new 1U (1.75-inch) and 2U (3.5-inch) rack and tower servers with the 5100 processors. SGI is using the new chip as part of an initiative it hopes will help bring the company out of bankruptcy. SGI, which has struggled in recent years, is restructuring its business and product line. The company is unveiling the Altix XE, a family of Linux-based servers and cluster offerings powered by Woodcrest 5150 CPUs. In addition, SGI is launching its Altix 450 system, a blade offering powered by Intels upcoming dual-core "Montecito" Itanium 2 chip, due later this summer. SGI officials say the new system will offer up to 2.5 times the performance of its current Altix 350 but will cost less. Customers will be able to configure the new 450s to optimize density, I/O or memory. In addition, SGI is equipping its current Altix 4700 blades with the Montecito chip for the same price as the current server running on single-core Itaniums. Rackable is introducing its C1000 line of 1U, 2U or 3U (5.25-inch) rack-mount servers that can come with the companys DC-power technology. John Hazard contributed to this report. Editors Note: This story was updated to include comments from Pag Gelsinger. Check out eWEEK.coms for the latest news, views and analysis on servers, switches and networking protocols for the enterprise and small businesses.