CNET News.com reports that the Xserve upgrade to Virginia Tech’s supercomputer cluster is now complete, but that it was built with machines unavailable to the public. According to Virginia Tech spokeswoman Lynn Nystrom, the university’s system is made up of 1,100 Xserves with dual 2.3GHz G5 chips, even though Apple currently only sells Xserve G5s with dual 2GHz chips. In related news, IBM claimed first place today in a supercomputer speed contest, beating out a Japanese machine from NEC. Researchers clocked the machine at a sustained performance of 36.1 teraflops. Since 2002, NEC’s Earth Simulator has held the top spot on a ranking of the world’s 500 fastest supercomputers while running at a speed of 35.9 teraflops.