Bruno Michel of IBM's Zurich labs say future computers will have many processors stacked together and cooled by water flowing between them.
The aim, he says, is to reduce computers' energy use rather than just to shrink them.
"In the past, computers were dominated by hardware costs -- 50 years ago you could hold one transistor and it cost a dollar, or a franc," Michel told BBC News.
The cost of building the next generation of supercomputers is not the problem, he says, it's the cost of running the machines.
"In the future, computers will be dominated by energy costs -- to run a data center will cost more than to build it," Michel says.
Building and running computer equipment consumes about 2 percent of the world's total energy, researchers say.
Michel and his team have built a prototype using the water-cooling principle. Called Aquasar, it occupies a rack the size of a refrigerator.
IBM estimates Aquasar is almost 50 percent more energy efficient than the world's leading supercomputers.