The "quad-core" processors, which boast improved performance over models with just one or two processing cores, could help the company win back market share lost to smaller rival Advanced Micro Devices Inc., analysts said. Processors with multiple cores can handle more complex jobs at once.

Intel rolled out four processors for servers under the Xeon 5300 branding, and another processor under the Core 2 Extreme series aimed at hardcore computer gamers, programmers and other people with heavy-duty computing needs.

The Core 2 Extreme chip is up to 80 percent faster than previous models, the Santa Clara-based company said. The Xeon 5300 chips use roughly the same power as previous generations while boosting performance as much as four times over single-core models.

Intel plans to release three more quad-core processors in the first quarter of 2007, including a more mainstream model for entertainment and multimedia uses under the name Core 2 Quad, and a Xeon processor designed for low-voltage uses and another for single-socket servers and workstations.

Intel, which is locked in a fierce battle for market share with smaller rival Advanced Micro Devices Inc., had originally promised the quad-core chips for mid-2007 but earlier this year announced it was ramping up production, beating Sunnyvale-based AMD to market by several months.

AMD, which has been stealing market share from Intel with chips that reviewers said were cheaper and faster to run, has said it expects to launch quad-core processors for its Opteron product line by mid-2007.

The battle has had an impact on Intel's financial health. The company announced a massive restructuring in September that called for a 10 percent reduction in staff or 10,500 positions to save $3 billion per year by 2008.

Intel executives hailed the quad-core launch as another key step toward reversing sinking profits and regaining lost market share. It also follows the launch this summer of its Core 2 Duo microprocessors, which deliver as much as 40 percent better performance while consuming as much as 40 percent fewer watts than previous models.

"We're back we're running hard and setting the pace for the entire industry," said Pat Gelsinger, Intel's senior vice president. "I think of this as the exclamation point on a wonderful year of products."

AMD executives on Monday promised a smooth transition to quad-core chips while seizing on a major design difference between the two companies' chips.

Intel's design packages together two dual-core chips that plug into a single processor socket, while AMD's will integrate the processors onto a single sliver of silicon, a design that AMD claims will offer higher performance and power efficiency.