Following several months of delays, AMD's newest chip, a quad-core server processor known as Barcelona, will launch today.

Barcelona is officially called Quad-Core Opteron, and is an important release for AMD. AMD has been losing ground in the server-chip market to rival Intel and hopes the new processor will reverse its fortunes.

But it won't be easy. While AMD struggled to get the Quad-Core Opteron out of its factories, Intel shipped newer, faster processors expected to compete more closely with the new chip, particularly in the market for high-end servers with four or more processors.

Nevertheless, AMD is counting on technical differences between its quad-core chips and those from Intel to offer better performance while consuming less power.

See also: Intel chip backed for $100 laptop

Nine versions of the Quad-Core Opteron will be available from today, all manufactured using a 65nm (nanometer) process. These are the first quad-core chips from AMD and the first server chips from the company made using this technology. Previous server chips were made using a 90nm process.

"We used this opportunity as we move from 90nm to 65nm to redesign the processor, to be able to optimise and get more efficiency out of it," said John Fruehe, AMD's worldwide business development manager for servers and workstations.

At the high end of the Quad-Core Opteron line up are chips designed for servers with four or more processors.

The 2GHz 8350 has a TDP (thermal design power) of 95W and is priced at $1,019 in 1,000-unit quantities, a standard measure of processor pricing. TDP does not indicate the amount of power that a processor consumes, rather it describes the maximum amount of heat that server makers must be able to dissipate from the chip in extreme circumstances.

The second Quad-Core Opteron designed for multichip servers is the 8347, which runs at 1.9GHz and has a 95-watt TDP. The chip is priced at $786.

The range of multi-chip servers also includes two models with a lower TDP, the 8347HE and 8346HE. With a TDP of 68W, these chips run at clock speeds of 1.9GHz and 1.8GHz, respectively. They are priced at $873 and $698.

All of the Quad-Core Opteron chips have 512KB of level two cache per processor core, and 2MB of level three cache shared by the four cores.

Five versions of the Quad-Core Opteron will be available for servers with one or two processors.

The Quad-Core Opteron 2350 and 2347 run at speeds of 2GHz and 1.9GHz and have a TDP of 95W. The chips are priced at US$389 and $316, respectively. The 1.9GHz 2347HE, 1.8GHz 2346HE, and 1.7GHz 2344HE have a lower TDP, at 68W. The chips will cost $377, $255, and $209.

AMD said the new chips are faster than previous Opterons, with a 2GHz Quad-Core Opteron running 79 percent faster than a 3GHz dual-core Opteron. Five single-core Opteron processors are required to match the performance of a single Quad-Core Opteron, the company said.

The Quad-Core Opteron has four processor cores on a silicon chip that also includes a memory controller hub and high-speed HyperTransport links. By comparison, Intel's quad-core processors have two dual-core silicon chips inside a multi-chip package that does not include the memory controller.

AMD has added new features to the Quad-Core Opteron designed to boost the chip's performance and lower power consumption relative to earlier Opteron chips. For example, each of the Quad-Core Opteron's processors and the memory controller have independent power supplies, which allows them to run at different clock speeds and reduce power consumption when they don't need to run at full speed.

"You're most likely going to have a quad-core processor with four different speeds because you've got four different utilization levels at any time," Fruehe said.

The chip maker also added a 128-bit floating point unit to the Quad-Core Opteron to boost performance for certain types of applications.

At the same time AMD will announce the availability of the Quad-Core Opteron, the company plans to say more than 50 systems based on the chips are now available from vendors like Sun Microsystems, Hewlett-Packard, IBM and Dell, among others.

If servers based on the Quad-Core Opteron chips turn out to be faster and more energy efficient than systems based on Intel's offerings, that edge may not last long. In November, Intel plans to refresh the bulk of its server chip lineup with a new family called Penryn. The Penryn server chips will be made using a 45nm process and will have more memory cache than Intel's existing server chips, giving them a boost in performance.

"We have a significant lead today and we believe we will have that lead with Clovertown, and once we have Harpertown with 45nm we will extend that lead further," said Adesh Gupta, regional platform architecture manager at Intel Asia-Pacific's Server Platforms Group, referring to code names for Intel's current and upcoming quad-core processors designed for two-way servers.

Later this year, AMD expects to release Quad-Core Opteron chips that run faster than the versions set to be announced Monday. One of those processors is a 2.3GHz Quad-Core Opteron SE designed for high-performance computers, set for release during the fourth quarter.

AMD plans to offer faster versions of the standard Quad-Core Opteron chips during the fourth quarter, with faster versions of the low-power HE chips due during the fourth quarter of 2007 or the first quarter of 2008.