But the Sun-Fujitsu servers create a potential dilemma for users because of the looming 2008 arrival of other systems based on a multicore and multithreaded UltraSparc processor codenamed Rock that Sun is designing itself.

Plans for the APL line were announced in June 2004. The new servers will use a Fujitsu version of UltraSparc called Olympus and are due to replace Sun's existing Sun Fire systems and Fujitsu's PrimePower machines. APL originally was schedule to debut last summer, but its release was delayed until next year.

That pushes it closer to the planned release of the Rock processor, which Sun said will appear in systems in 2008. Rock will be aimed at what Sun describes as data-centric loads such as managing and analyzing information used in data warehousing and data mining. The company's other multithreaded processor, called the T1 and originally codenamed Niagara, is aimed at network-centric workloads, such as Web-facing Java applications, according to Sun.

Nathan Brookwood, an analyst at Insight64 in Saratoga, Calif., said the APL line "should be of decreasing interest for most Sun customers" because the window between its expected availability and that of Rock-based systems seems to be closing.

But it's uncertain whether systems built around Rock will be a substitute for all the processing workloads that APL will be able to handle, said Gordon Haff, an analyst at Illuminata Inc. in Nashua, N.H. "I don't think there is any guarantee that Rock is going to outperform the Fujitsu-Sparc processors across all workloads," he said. "Sun certainly hasn't said that."