Sun said servers fitted with the processor would offer a 20 percent performance boost over models with previous UltraSPARC III offerings, the fastest of which was a 750MHz model.
The 900MHz chip uses several engineering and manufacturing advances, such as copper interconnects, to help boost performance.
The company said the chip will be available immediately in its Sun Fire 3800, Sun Fire 4800 and Sun Fire 4810 servers, as well as its 6800 Midframe server line.
The 900MHz chip is also used in high-end Sun servers, such as the Sun Fire 15K--or Starcat--server, launched in September.
Sun has been shipping the 750MHz version of the current UltraSPARCIII for some time. But the faster, 900MHz version has been faced with delays, prompting the company to push back its introduction until this year.
Analysts say the company has its work cut out for it. It must convince customers to transition from the previous generation, UltraSPARC II chip to the newest UltraSPARC III.
Sun said the 900MHz chip helps round out its server product lines.