Unisys has added on-demand processing power to its business servers, claiming it is the first time that a "true" version of the technology has been available for Windows and Linux servers.

The ES7000 servers will now give Intel-based systems a feature that's already available on its mainframes and on machines offered by some rival hardware vendors. The company said the new servers were aimed at a growing market as the popularity of Unix/RISC dwindles as companies go for Intel chips on Windows and Linux in data centres.

Unisys has produced a series of ES7000 Real-Time Capacity (RTC) models that include four inactive Intel processors along with four, eight or 12 active ones. Unisys will charge a 10 percent premium upfront for the extra CPUs. But if a user eventually turns them on, the final cost will be no different than if they were initially purchased as active processors, said Mark Feverston, director of platforms for systems and technology at Unisys.

Four ES7000 users said the capacity-on-demand feature makes financial sense only if processing demand is set to increase in the future.

Denis Baker, CIO at Sarasota Memorial Hospital in Florida, said he doesn't need to have extra processing power on hand for the 24 and 12-processor ES7000 systems he runs. "It's not like we're hosting websites and have unknown demand that's going to hit," Baker said. "Our user load is more static than that."

Microsoft is certainly happy about the move. VP of its Enterprise and Partner Group, Simon Witts, said: "Businesses have a critical need for IT infrastructure solutions that help drive growth while controlling costs, which becomes a more difficult challenge in the face of change. In bringing capabilities like 'capacity on demand' to Windows Server, Unisys will help customers operate highly efficient data centres under any circumstances and meet their business objectives.”