AMD unveiled today its first first energy-efficient x86 server processors with four processing cores and an integrated memory controller all in a low 55-watt ACP thermal envelope.

According to AMD, ACP (or the Average CPU Power) metric represents processor power usage, including cores, integrated memory controller, and HyperTransport technology links, while running a suite of typical and relevant commercially useful high utilization workloads to be more indicative of the power consumption that end-users can expect.

Randy Allen, corporate vice president and general manager, Server and Workstation Division, AMD said that the new 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.

Quad-Core AMD Opteron HE processors are available in both the 2300 and 8300 Series for two-, four- and eight-way rack servers and blades.

Although the company announced the new lineup in September, AMD was forced to the push the shipment of its new Opteron processors to the fist quarter of 2008 because of an error that was located on the L3 cache of the chip.

Earlier this month, AMD announced that its 45-nm “Shanghai” server chip is on track to begin production in the second half of this year and it will include coherent HyperTransport 3.0 for processor-to-processor communication, an increased shared Level-3 cache of 6MB instead of 2MB, as well as core and instruction-per-clock (IPC) enhancements.

Also AMD updated its server roadmap and new to its lineup is the 6-core server processor “Istanbul,” which AMD said fits within the current socket F1, and will be available in the second half of 2009, aimed at allowing OEMs to preserve platform investments while increasing system performance-per-watt. “Istanbul” is planned to be available for configurations of 2P and supports AMD’s Direct Connect Architecture.

In 2010, AMD expects to introduce a third-generation Opteron processor Socket G34 platform that will contain DDR3 memory capabilities and the AMD RD890 chipset for non-coherent HyperTransport 3.0, as well as an additional HT link.