AMD announced on Wednesday it was shipping the quad-core Opteron chip in volume after fixing a bug, but concerns are being raised about AMD's abilities to stick to its product roadmap, analysts said.

The chip, code-named Barcelona, was delayed in December because of a bug in the L3 cache that caused applications to fail. The chip maker started shipping the chip in September in limited quantities to vendors running high-performance computers.

The new chip is shipping in volume to computer makers, including top server vendors Hewlett-Packard, Sun, IBM, and Dell.

AMD didn't feel comfortable shipping a chip with the problem, said Steve Demski, AMD Opteron product manager. "We're glad to have this one errata behind us. This is a product we've been waiting to offer for a long time."

The Barcelona chip created much enthusiasm 18 months ago as the first quad-core chip when it broke away from Intel's traditional multicore architecture, said Richard Doherty, research director at The Envisioneering Group. In an industry that has its own challenges, customers were waiting for Barcelona and still kept waiting until interest waned, Doherty said.

"The goodwill and camaraderie and enthusiasm at a peak two years ago has more than waned. In the silicon [industry] you have to ship on time," Doherty said.

Computer makers want to offer customers an alternative, but they need from chip makers a clear message and dependable delivery schedule from which they can plan shipments. "Nearly everyone wants a robust competitive economy besides Intel," Doherty said, referring to Intel's dominant position in the chip market.

However, AMD did not deliver chips on time, and customers shifted to Intel quad-core processors, which have stayed on schedule and fairly faithful to their roadmap. Intel currently has a sizeable lead over AMD in the global microprocessor market. Meanwhile, AMD has filed antitrust lawsuits and complaints globally accusing Intel of anticompetitive behavior.

The Envisioneering Group, which benchmarks chips, hasn't yet received a Barcelona chip from AMD for benchmarking despite requests.

"[It] is not good because every vendor who has said we are going with multiple suppliers wanted [AMD] to succeed better. Now there's just tremendous doubt," Doherty said.

Barcelona's bugs and delays cost AMD momentum, time, money, and credibility, said Nathan Brookwood, principal analyst with Insight 64. The company has a lot of work to do with customers and computer makers to build back its reputation, he said.

"Now that the product is available and [AMD] put the chips in systems, they can get back on track" and compete with Intel, Brookwood said. "There's been a lot of concern, and what AMD's saying here, is we've got it under control."

The Barcelona delays have also generated concern about AMD's ability to deliver its next quad-core server chip, Brookwood said. Code-named Shanghai, the chip will be manufactured using the 45-nanometer process and is due to go into production in the second half of 2008, he said.

"They said they will be able to. It's just not enough to say that, they have to do that. If they can, they can be back in the game," Brookwood said.

Intel is also making moves in the multi-core game. As the quad-core Shanghai goes into production, Intel plans to ship a Xeon server chip, code-named Dunnington, which will have six cores. Intel will start shipping server chips based on its new architecture, code-named Nehalem, in the second half of 2008. Nehalem chips will come with four and eight cores.

AMD said that in the "latter half" of 2009 it will ship its next server chip, code-named Montreal, which will come with four and eight cores.