"Every data center does move water. We get that water closer to the point where you're actually generating heat," Cooley says.

Sun isn't bringing water into the servers just yet.

"What comes along with it is the need to bring water into every server, and all the plumbing issues," Cooley says. "Sun does not have a product in this space right now. But every vendor is looking into this."

Rather than put water inside the servers, Sun placed the water cooling technology in the Modular Datacenter, which is essentially a computer room in a large box that's been generally available since the end of January. Standard servers are placed inside the box, bringing them closer to water and reducing the amount of hot air that needs to be moved around a data center.

IBM did Sun one better with the System p5 575, which uses the Power6 chip. A cabinet that holds 14 servers pumps cold water through pipes onto a little copper plate that sits right on top of the chip, Seminaro explains. The cabinet contains 7.2 gallons of purified water, which is endlessly recirculated, remaining in the cabinet for the life of the product. A connection to a building's plumbing system is necessary for the heat to be transferred from the product to the customer's water pipes.

Naturally, customers may worry about a leak inside the system ruining their expensive processors. IBM uses a corrosion-resistant water distribution system to minimize that risk, and water is kept at a temperature that causes no condensation, Seminaro says. Leaks are possible, he acknowledges. But IBM is confident enough that it plans to expand water cooling to more servers.

"We're evaluating it now," Seminaro says. "We will definitely put it into more of our platforms. We started here because in the world of technical computing there is a real desire for a tremendous amount of compute capacity in a given location."

The System p5 575 with water cooling has 448 processors and is capable of performing trillions of operations per second. Water is about 4,000 times more efficient than traditional air cooling, IBM notes in a video on its Web site. Actual energy savings aren't quite that impressive. The number of air conditioning units can be reduced by 80 per cent, and energy consumption for data center cooling is reduced by 40 per cent, IBM says. Big Blue says its scientists are working toward "direct on chip" water-cooled systems that will be even more efficient by bringing water all the way to the hottest parts of a computer.

While IBM recently rediscovered water cooling, HP has been researching water cooling since 1999 and began offering an HP-branded system about four years ago, says Wade Vinson, HP's power and cooling architect. Like Sun, HP is not bringing water directly into the servers. HP's Modular Cooling System is a water-cooled rack that gets water from one of three sources: a direct connection to the building's chilled water system, a dedicated chilled water system, or a water-to-water heat exchanger unit connected to a water system.