Google is working on a secret weapon in its quest to dominate the next generation of Internet computing.

It’s installing one of the world’s most powerful supercomputers — part of a worldwide computing system known as the Googleplex, reportedly with more than 450,000 servers in at least 25 locations around the world, with plans for 800,000 by 2011.

The new installation, near the Oregon-Washington border, is at the intersection of low-cost electricity and readily accessible data networking — the backdrop for a multibillion-dollar face-off with Microsoft and Yahoo that will determine dominance in the online world in the years ahead.