The Blue Gene/L supercomputer has broken its own record to achieve more than double the number of calculations it can do a second.
It reached 280.6 teraflops - that is 280.6 trillion calculations a second.
The IBM machine, at the US Lawrence Livermore National Laboratory, officially became the most powerful computer on the planet in June.
The fastest supercomputers in the world are ranked by experts every six months in the Top 500 list.
Blue Gene's performance, while it has been under construction, has quadrupled in just 12 months.
Each person in the world with a handheld calculator would still take decades to do the same calculations Blue Gene is now able to do every second.
BlueGene/L points the way to the future and the computing power we will need to improve our ability to predict the behaviour of the stockpile as it continues to age
Linton F Brooks, NNSA
Linton F Brooks from the National Nuclear Security Administration (NNSA) formerly unveiled it at the Lawrence Livermore National Laboratory on Friday.
The completed Blue Gene/L joins another supercomputing team-mate, called ASC Purple, to get to work on safeguarding the US's nuclear stockpile.
Purple can do 100 teraflops while it carries out simulations of nuclear weapons performance.
"The unprecedented computing power of these two supercomputers is more critical than ever to meet the time-urgent issues related to maintaining our nation's ageing nuclear stockpile without testing," said Mr Brooks.
"BlueGene/L points the way to the future and the computing power we will need to improve our ability to predict the behaviour of the stockpile as it continues to age."
The machines are part of a decade-long project to develop the fastest computers in the world.
Blue Gene will work on materials ageing calculations, molecular dynamics, material modelling as well as turbulence and instability in hydrodynamics.
Purple will then use that information to run 3D weapons codes needed to simulate nuclear weapons performance quickly.
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That analysis had previously taken place in underground nuclear tests.
Their massive brains will be able to perform half a petaflop together - that is half a quadrillion (1,000,000,000,000,000) calculations a second.
In a recent demonstration, Blue Gene/L achieved another first by running a materials science application at 101.5 teraflops, sustained over seven hours on the machine's 131,072 processors.
Supercomputers are playing an increasingly crucial role in working out complex problems quickly.
They recently became a major tool in a range of advanced biological applications, from helping to piece together fragmented DNA information to the design of new drug molecules.
Astronomers have also borrowed their brains to re-create how the Universe evolved into the shape it is today.
Their massive simulation and processing power have also been used improve the accuracy of weather forecasts, help design better cars, and improve disease diagnosis.
Supercomputers step up the pace
A partially built supercomputer has kept its spot at the top of the list of most powerful machines on the planet.
The BlueGene/L machine currently under construction at the Lawrence Livermore National Laboratory in the US was crowned top number-cruncher.
Its current processing peak of 136.8 teraflops will be doubled by time construction work is completed.
As a result, the organisation drawing up the list expect it to dominate the rankings for some time to come.
The Top 500 list is drawn up every six months and is a snapshot of the most powerful machines on Earth.
IBM's BlueGene/L took the top spot for the second time largely because its processing capacity doubled in size since the last list was drawn up.
When it is finished the machine will use 65,536 processors to tackle problems such as molecular dynamics, metrial modelling as well as turbulence and instability in hydrodynamics.
In the last list, released in November 2004, the machine's peak performance was 70.72 trillion calculations every second - a measurement known as teraflops.
TOP FIVE SUPERCOMPUTERS
IBM BlueGene supercomputer
1) BlueGene (LLNL) - 136.8tflops
2) BlueGene (NY) - 91.2 tflops
3) Columbia - 51.87 tflops
4) NEC Earth Simulator - 35.86 tflops
5) MareNostrum Cluster - 27.91 tflops
The machine in second place is also a BlueGene system that was recently installed in IBM's Thomas J Watson Research Center in New York. At its peak that machine has proved capable of cranking through 91.2 teraflops.
As well as dominating the top two places, IBM is the dominant supplier of supercomputers on the list. In all 51.8% of the machines on the list sport its badge.
Silicon Graphics, NEC, Hewlett-Packard and Cray all have machines in the list. Cray's newest machine, the Red Storm, made it to the number 10 slot on the list.
Top supplier of the chips to do the number crunching was Intel. Its hardware was used in 333 of the systems listed. Also, five of the top 10 machines listed by the Top 500 organisation are BlueGene computers.
Third in the Top 500 list was Nasa's Columbia supercomputer at the Ames Research Center in California.
In the six months since the last list was drawn up half of the computers listed have been replaced by more powerful machines, a testament to the pace of innovation and to the increasing power found in silicon.
The basic power requirement needed to get on to the Top 500 list is 1.166 teraflops, a leap upwards from the basic 850.6 gigaflops benchmark from the November 2004 list.
The Top 500 list is compiled by Hans Meuer of the University of Mannheim in Germany, Erich Strohmaier and Horst Simon of NERSC/Lawrence Berkeley National Laboratory in the US and Jack Dongarra of the University of Tennessee in Knoxville.
The 25th edition of the list was unveiled at the International Supercomputing Conference held from 21-24 June in Heidelberg, Germany.
Supercomputer to build 3D brain
Neuroscientists are to build the most detailed model of the human brain with the help of an IBM supercomputer.
Experts at the École Polytechnique Fédérale de Lausanne, Switzerland, will spend the next two years creating a 3D simulation of the neocortex.
This is the part of the brain thought to be responsible for language, learning, memory and complex thought.
The researchers believe the project will give them fresh insights into the most remarkable organ in the body.
"Modelling the brain at the cellular level is a massive undertaking because of the hundreds of thousands of parameters that need to be taken into account," said Henry Markram, the EPFL professor leading the project.
The Swiss scientist and his colleagues will have at their disposal an IBM's eServer Blue Gene supercomputer.
Up the pace
The system to be installed at their EPFL lab will take up the floor space of about four refrigerators, and will have a peak processing speed of at least 22.8 trillion floating-point operations per second (22.8 teraflops), making it one of the most powerful supercomputers in the world.
Five years ago, no supercomputer in the world was capable of more than one teraflop.
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The effort has been dubbed the Blue Brain Project. It is a daunting undertaking given the myriad of electro-chemical connections that must be mapped.
By using a supercomputer to run experiments in real time, Professor Markram hopes to accelerate substantially the pace of brain research.
"With an accurate computer-based model of the brain much of the pre-testing and planning normally required for a major experiment could be done 'in silico' rather than in the laboratory.
"With certain simulations we anticipate that a full day's worth of 'wet lab' research could be done in a matter of seconds on Blue Gene."
The Blue Brain Project will start with the neocortex but scientists expect eventually to produced a 3D model of the entire brain.
Researchers expect not only to get a better understanding of how the organ is wired up but also to use that "atlas" of neurocircuitry to probe how the brain functions - and malfunctions.
The scientists say the project could lead, for example, to new ideas on how psychiatric disorders develop - illnesses such as autism, schizophrenia, and depression.
Supercomputers have recently become a major tool in a range of advanced biological applications, from helping to piece together fragmented DNA information to the design of new drug molecules.