IBM said Wednesday that the company built 243 computers on the list of the world's top 500 supercomputers in the world. However, the bigger story may be AMD's continued rise in the rankings. While AMD processors are only in 81 supercomputers, that 's up dramatically from 25 last year.

Intel processor-based systems are down over the same period, from 333 to 301. Similarly, the Itanium processor has continued to become less relevant, falling from 79 last year to 37 systems as of the current report. Intel has been locked in a tight battle with AMD over the past year, and has seen its market share fall in desktops, laptops and now servers.

IBM said that the company's low cost and flexible supercomputers were driving growth in the sector. "Whether we are talking about improving the accuracy of weather forecasts, designing better automobiles or improving disease research, we are seeing the advent of a new supercomputing age," Deep Computing vice president Dave Turek said.

Second to IBM is Hewlett Packard, with 154 systems. No other manufacturer had more than 5 percent of the list, or 25 systems. Even so, many smaller names were able to crack the top 10, including Silicon Graphics in fourth, Bull SA in fifth, Dell in sixth, and NEC/Sun in seventh, Cray in ninth, and NEC in tenth.

By operating system, Linux by far was the operating system of choice, covering 73 percent of the list. Unix was a distant second with 20 percent. Microsoft's Windows was only on two systems, with one of its computers based on Windows Compute Cluster Server 2003 reaching a performance of 6 teraflops, placing it 131st on the list.