AMD has shown off a lab version of its "Barcelona" quad-core Opteron 8000 server chip and announced it will begin selling the product in the second quarter of 2007.

The chip will be aimed at high-end users dealing with commercial workstations and servers, who could see performance improvements of up to 70 percent in database applications and 40 percent in floating-point applications compared to AMD's dual-core "Rev F" Opteron.

The demonstration was AMD's second effort to show that it is keeping up with quad-core chips from rival Intel - it also launched its "4x4" Quad FX Platform, a motherboard with two dual-core Athlon 64 FX-70 series chips intended for the desktop gaming market.

Intel lost significant market share to AMD in 2006 and was criticised for being slow to produce chips that emphasised power efficiency instead of pure calculating speed. Intel has bounced back in recent months with the launch of dual-core chips including the Core 2 Duo for desktops and Xeon 5100 "Woodcrest" for servers. Intel reached the market first in November with quad-core chips, with the Core 2 Extreme QX6700 for gamers and Xeon 5300 for servers.

Intel has also led the industry in converting its chip designs from the 90nm process to 65 nm, including all four processors mentioned above. In response, AMD has criticised Intel's quad-core design as merely gluing two dual-core Woodcrest chips together, whereas the Barcelona chip includes all four cores on a single piece of silicon. Analysts are divided on the impact of that distinction, and say they cannot measure the difference until they compare benchmarks from both finished versions.

Still, AMD trumpeted Barcelona as an engineering achievement that marks the company's shift to 65nm architecture. By shrinking the processor die, AMD is able to improve power efficiency and squeeze an extra level of shared cache memory onto the design, said John Fruehe, AMD's worldwide market development manager for server and workstation products.

"As you add more cores, it becomes less about brute force and more about the efficiency of how many things you can do at once, and how efficiently you can order them," he said. "From a customer perspective, those who will see the biggest bang for their buck with quad-core are people running applications like larger databases. The more threaded an application is, the more benefit you get."

The users who will see the greatest return on their quad-core investment are users of multithreaded applications like CRM (customer relationship management), ERP (enterprise resource planning), e-commerce and virtualization, Fruehe said.

AMD will first launch the Barcelona design on a four-socket board (running four quad-core chips) and a two-socket board (running two quad-core chips). The company will wait until later in 2007 to launch single-socket Barcelona boards, which are used mainly to develop new applications for the larger servers or to run Web farms to handle multiple simultaneous processing requests.

AMD expects servers vendors such as Dell, HP, IBM and Sun to adopt the new technology for their servers in 2007, although none of those companies has yet made a public announcement.