Addison Snell, an analyst at IDC, said the market research firm is seeing new technical computing users who are migrating from workstations to clusters. "There is definitely the opportunity for growth," Snell said of Microsoft's prospects.

He predicted that the appeal of Windows for SGI and its Altix system will be the ability to capture lower-end users. "SGI has been hemmed into the higher end," he said.

IDC forecast that the HPC market will grow about 9 percent annually, from more than US$10 billion worldwide last year to $14.3 billion by 2010.

The Intel Xeon-based Altix XE servers start at a little above $3,000.