Intel's decision to begin shipping versions of x86 processors that are capable of 64-bit computing has slowed down the adoption of the company's high-end Itanium processors, admitted a company senior executive at the Intel Developer Forum (IDF) in San Francisco.

"I would be remiss to say that the impact was zero, but I would say that the impact was mainly noise and perhaps confusion," said Abhi Talwalkar, vice president and general manager of Intel's Enterprise Platform Group, "I think it has set us back several months," he added.

But Talwalkar said that although sales of Itanium had not met Intel's target, the company's decision to support 64-bit extensions in x86 processors had not affected Itanium's competitiveness against RISC processors from companies like IBM and Sun Microsystems.

After initially expressing reluctance to the idea, Intel last February followed rival AMD' s lead and announced plans to make its 32-bit Xeon and Pentium processors capable of processing data in larger, 64-bit chunks, than they could previously handle, and thus allow them to run 64-bit applications.

Intel had been reluctant to support the 64-bit extension of x86, a technology that it calls EM64T and AMD calls AMD64, for fear that it would hamper the adoption of the Itanium processor line, which is also designed for 64-bit applications. Programs written for 32-bit x86 processors do not perform as well on Itanium as they do on processors that extend the x86 instruction set, and that fact ultimately forced Intel to develop EM64T, analysts say.

Intel began shipping its first EM64T processor, a Xeon chip code-named Nocona, in August.

Though Intel had at one point positioned Itanium as the general purpose enterprise processing platform of the future, Talwalkar's statements reflected the company's growing realisation that 64-bit versions of x86 are unlikely to be displaced by Itanium, said Gordon Haff, an analyst with industry research firm Illuminata.

"The reality is, to the degree that Itanium had any ambitions for the 64-bit market as a whole, EM64T and Opteron really kind of blew that out of the water," Haff said.