The Pittsburgh Supercomputing Center has placed an order for the latest model of Cray Inc. supercomputer, the Seattle company announced this week.

The new computer would be a version of Red Storm, a $93 million computer that Cray is building for Sandia National Laboratories, a nuclear weapons lab in Albuquerque, N.M. Sandia's computer will be capable of 40 trillion calculations per second, and will be one of the most powerful in the world.

But Michael Levine and Ralph Roskies, co-scientific directors of the Pittsburgh center, say they haven't yet come to an agreement with Cray about how powerful their version of Red Storm will be. The center, which gets most of its money from the National Science Foundation, can't afford the same level of performance as a nuclear weapons lab.

Cray said it will deliver Red Storm to Pittsburgh in the third quarter of this year.

For the past three years, the Pittsburgh center's workhorse has been Lemieux, a computer that fills the space of a basketball court in the basement of the Westinghouse Energy Center in Monroeville. Capable of performing up to 6 trillion calculations per second, it was built and operated with a three-year, $45 million grant from the NSF.

As of last fall, Lemieux was ranked as the 12th most powerful computer in the world, down from third place when it debuted in 2001. Levine and Roskies said Lemieux likely will continue to be useful for another two or three years.

But the 3,000-processor machine can't be readily expanded ---- Hewlett-Packard no longer makes the Alpha processors it uses ---- and researchers demand more power for ever-more-complex problems.

Like Lemieux, Red Storm would use thousands of microprocessors. But Red Storm would incorporate those processors into a single machine, rather than linking together hundreds of separate computer servers, as does Lemieux.

The Pittsburgh Supercomputing Center serves as a nationwide computing resource for nonclassified research. It is operated jointly by the University of Pittsburgh and Carnegie Mellon University, along with Westinghouse Electric Co.