AMD's quad-core Barcelona processors are not yet fast enough to beat Intel's Core 2 processors, despite claimed performance improvements of up to 40 per cent over current offerings, Gartner believes.

"AMD's performance estimates are based on a leisurely 2GHz clock speed, which is lower than expected and suggests room for significant gains," said Gartner analysts Martin Reynolds, John Enck and Stephen Kleynhans in a new advisory.

"The low clock speed leads us to believe that AMD has had implementation issues with the design. Gartner expects these issues to be corrected late in 2007, leading to a healthy improvement in performance.

"Although Barcelona will enable AMD to tackle the performance gap that Intel opened up with its quad processor Core 2 products, the lower than expected clock speed means that AMD will not recover processor performance leadership against Intel's current products."

Although the next version of AMD's quad-core chip, due out at the end of the year, could boost performance by 20 per cent, the chip will go head to head in the market with Intel's next-generation Penryn processor.

Gartner explained that the performance gain from AMD's quad-core architecture is derived largely from having four processor cores in the component, double the two cores in its current product line.

Barcelona processors also have a new core design that allows higher performance at lower frequencies.

"We believe that, in the common case of two-way four-core servers, Opteron and Xeon performance will be close," said the Gartner analysts.

"Barcelona has a new floating-point unit that, with recompilation, will deliver disproportionate performance gains in some applications.

"Given that the pin-compatible Barcelona parts can be retrofitted into recent Opteron-based servers, high-performance computing users may begin retrofitting existing systems."

The analyst firm expects Barcelona to take a "leadership position" in four-way systems because it believes that "Intel does not yet have a compelling four-way architecture".

However Gartner expects that Intel will have rectified this late in 2007, when it is expected to deliver high-bandwidth technology for its existing quad-core components.

"Barcelona will keep AMD in the game, but the company must match Intel's current pace of innovation to avoid being repositioned as a cut-price product," Gartner said.