Sun Microsystems has doubled the capacity of its Niagara servers with the four-socket Sparc Enterprise T5440 system, designed for running corporate databases and ERP (enterprise resource planning) applications.

The server houses up to four of Sun's UltraSparc T2 Plus processors, up from two in the previous model, and expands the main memory to a maximum 512G bytes. Each processor has eight cores that can each run eight computing threads, or sets of software instructions, simultaneously. The servers are also sold by Sun partner Fujitsu.

Sun has positioned earlier Niagara servers primarily for network-facing applications or Web-tier work, but the newer machines are powerful enough to run large OLTP (online transaction processing) databases and packaged software from the likes of Oracle and SAP, said Rick Hetherington, the CTO of Sun's Microelectronics Group.

"I wouldn't recommend this for a Web server, it would be a little bit of an overkill," he said.

The support for larger memory configurations also makes the T5440 good for virtualization and server consolidation, Hetherington said. The machines come standard with Sun's Solaris 10 OS and its Solaris Containers and Logical Domains virtualization software.

At US$45,000, the entry price is almost three times that of the two-socket T5420 launched in April. Sun said that's because the base configuration of the T5440 is more powerful and qualifies it as a "midrange" server. It includes two 1.2GHz T2 Plus processors, 32G bytes of memory and two 146G byte hard disks.

Sun has taken a different track from competitors with its processor designs. The T2 keeps the clockspeed low -- a maximum of 1.4GHz per core, compared with 5GHz for IBM's Power6 -- but can process more threads simultaneously and includes on-chip memory controllers to keep the threads filled with data.

IBM refreshed its own Unix server line last week, and Sun and IBM both claimed to give the best performance and power efficiency. Dan Olds, principle analyst at Gabriel Consulting Group, said it depends how the servers will be used.

"Customers need to test these systems on a workload-by-workload basis," he said. "There aren't many general rules of thumb here. It's going to vary by what you are doing and the application."

The Niagara servers seem to be doing well for Sun, which has otherwise lost share in the server market. Sun said its revenue from Niagara systems increased 84 percent in the year ending June 30, accounting for $1.1 billion in business.

Jean Bozman, a research vice president with IDC, said one advantage of the T2 systems is that they can run applications that were developed for earlier Sparc servers. "That's good news for customers," she said.