Advanced Micro Devices on Monday introduced five quad-core Opteron processors that the chipmaker described as energy-efficient.

The chips include three additions to AMD's 2300 series and two to the 8300 series. The new processors carry HE, which stands for highly efficient, with the model number.

The chips have an average CPU power of 55 watts and are designed for two-, four-, and eight-way rack servers and blades. The model numbers are the Opteron 8347 HE, 8346 HE, 2347 HE, 2346 HE, and 2344 HE.

"Our new quad-core AMD Opteron HE processors were designed to help datacenter managers who see power consumption and virtualization as the keys to solving their overall performance equation," said Randy Allen, corporate VP and general manager of AMD's server and workstation division, in a statement.

AMD last week unveiled its two-year product road map for servers and workstations. The plans included the company's first six-core chip, scheduled for release next year, and a 12-core processor on a new platform in the first half of 2010.

The new products, code-named Istanbul and Magny-Cours, respectively, would be 45-nanometer processors versus the 65-nm products AMD ships today. The smaller the size, the more transistors that can be packed on a single die, boosting overall performance at the same or lower power consumption.

AMD is on target to ship its first 45-nm server chip, code-named Shanghai, in the latter part of this year, which would be about a year after Intel shipped its first products using the next-generation manufacturing process that makes it possible to shrink transistor size. Shanghai will be a four-core processor that delivers 25% better performance than the company's current 65-nm quad-core Opteron, formerly known as Barcelona. Shanghai also will ship under the Opteron brand.