Dell Inc. is ending its support for Intel Corp.'s Itanium processor, an Intel spokeswoman said, closing the door on a product line that was a marginal part of Dell's server strategy. Itanium is a processor for high-end servers in supercomputing. Intel had once hoped to make Itanium the processor of choice for 64-bit computers. However, it uses a different instruction set than the 32-bit x86 Xeon processor, and software developers initially balked at having to port all their applications to an unfamiliar instruction set. The chip maker has since backed off its original statements about Itanium and is now promoting the chip as a high-performance replacement for RISC (reduced instruction set computing) processors in Unix servers from companies such as Sun Microsystems Inc. and IBM Corp. Hewlett-Packard Co. (HP), a co-designer of the processor, has embraced Itanium as the processor of choice for its high-end servers, and companies such as Fujitsu Ltd. and NEC Corp. also sell servers with the processor. Dell's server business, unlike those of HP, IBM, and Sun, grew along with the introduction of Intel's Xeon processor in the mid-1990s. Xeon changed the server market, coming in as a much cheaper alternative to RISC processors that could run Microsoft Corp.'s Windows and the Linux operating system. Dell's initial forays into the server market consisted of relatively inexpensive x86 servers, a type that today makes up about 90 percent of all servers shipped worldwide. After Advanced Micro Devices Inc. demonstrated that 64-bit extensions to the x86 instruction set offered a smoother transition to 64-bit computing, Intel released a version of Xeon with similar technology, and Dell now offers 64-bit Xeon processors across its product line. Dell was never a big Itanium customer, said Erica Fields, an Intel spokeswoman. "We've got a host of [server vendors] that sell Itanium. Dell was one of them, but frankly, their impact on sales has been negligible." After Intel dropped its plans to make Itanium its primary server processor, it also stopped developing chipsets for the processor, leaving that to partners such as HP, Fujitsu and others, said Gordon Haff, principal analyst with Illuminata Inc., in Nashua, New Hampshire. Dell does not invest nearly as much money in research and development as do those companies, and it really wasn't in a position to develop a chipset for Montecito, the dual-core version of Itanium that is scheduled to launch this year, he said. "It's not like Dell had been making investments in Itanium and suddenly decided it wasn't going to do that and pull back its support. It had a relatively older product it wasn't promoting at all, and it really doesn't have a near-term path where it could move forward if it wanted to," Haff said.