RICHMOND, Va. (AP) - A supercomputer made from 1,100 off-the-shelf Apple Macs at Virginia Tech now ranks third among the world's 500 fastest supercomputers, many of which handle with ease 1 trillion calculations per second. The Terascale Cluster computer, nicknamed "Big Mac" by some, conducts 9.6 trillion calculations per second, zipping along with 2,200 IBM microprocessors not unlike those found in high-end consumer desktop computers. "These powerful new machines . . . as our team at Virginia Tech has just demonstrated, are now within reach of most major corporations," said Hassan Aref, dean of Virginia Tech's College of Engineering and a former chief scientist at the San Diego Supercomputer Center. The Top 500 is a twice-a-year listing started in 1993 to provide a "Who's Who" of hot computers, spotting and tracking trends in high-performance computing. The Virginia Tech-Apple effort demonstrates the power of clustering, the linking of hundreds or thousands of computers to tackle massive projects, a trend that began a few years ago, according to listmeister and timekeeper Jack J. Dongarra of the University of Tennessee. The ranking by the Top 500 project will be formally announced Nov. 18 at the Supercomputing Conference in Phoenix. Theoretically, Big Mac could handle a potential 17 teraflops, or 17 trillion operations per second. That still falls short of the No. 1 machine, Japan's Earth Simulator, whose 5,000-plus processors keep it on top with 35.8 teraflops, with the potential of another 5 teraflops. A dedicated weapons computer at Los Alamos National Laboratory, the ASCI Q system, holds the current No. 2 spot. Big Mac began taking shape this summer soon after Apple unveiled its new G5 Power Macs, a slick personal computer lauded as among the world's fastest. The supercomputer will cost $5.2 million - including cables - over five years, compared to the tens or hundreds of millions of dollars for other big-boy supercomputers. Japan's Earth Simulator is said to have cost at least $350 million. Virginia Tech students and faculty began unpacking the computers in September, trying to meet the Oct. 1 deadline to create a supercomputer fit for current Top 500 consideration. "Modern engineering and science requires high-level computing for all kinds of tasks," Aref said in describing huge, intricate chores best handled by powerful, lightning-fast computers. Virginia Tech plans to unleash Big Mac on the school's growing research interest in such areas as nanoelectronics, aerodynamics and the molecular modeling of proteins.