Details about Sun's new Opteron-based servers - codenamed Galaxy - have leaked onto the Web.

An internal document was briefly available on Sun's own website that gave the first outline of its next-generation of servers. According to the document - a PDF presentation by Sun's chief technologist Ambreesh Khanna - Sun plans to release four models of Galaxy servers by year's end.

On the roadmap are two entry-level servers, a 1U (4.4 cm) dual-processor server with two PCI-X (Peripheral Component Interconnect - Extended) slots, two hard drives, and up to 16GB of RAM, and a larger 2U system that can contain the same amount of processors and memory, but will have four hard drives and five PCI-X slots.

At the high end will be two 4U machines, one that will support four processors and as much as 32GB of memory and a second eight-way system with as much as 64GB of memory. Both of these systems will have four hard drives and will support the PCI Express interconnect, but the eight-way machine will have eight PCI Express connections, two more than the four-way system.

Sun has been unusually tight-lipped about this line of servers which are being designed by Sun co-founder Andreas Bechtolsheim.

Bechtolsheim left Sun in 1995, but returned in February 2004 when the server design company that he had founded, Kealia, was acquired by Sun. His team has been working on Galaxy since the acquisition.

In February, Bechtolsheim said that Sun expected their new AMD systems to outperform Intel's Xeon products in both clusters of two-way servers and larger multi-processor servers.

Galaxy will also include ultra-thin Opteron blade servers designed to fit into the same chassis as Sun's blade servers based on its Sparc processors, said Sun engineer Geoff Arnold in a recent blog entry.

With the larger system configurations and dual-core processors, and 64-bit extensions to the x86 instruction set, the Galaxy servers will make interesting systems, said John Groenveld, an associate research engineer with Pennsylvania State University's Applied Research Laboratory. "I don't know whether Galaxy will revolutionize the [64-bit x86] market as IBM, Hewlett Packard, and Dell also sell 64-bit hardware," he said

Sun declined to comment.

Tom Krazit contributed to this report