Eight months after it agreed to begin using Intel Corp.’s x86 chips again, Sun Microsystems Inc. last week announced a pair of rack-mounted servers built around Xeon processors. The Sun Fire X4450 can hold four of Intel’s Xeon 7300 quad-core processors; the Sun Fire X4150 has two sockets and can support Intel’s older Xeon 5300 quad-core devices or its dual-core chips. Bill Heilman, a platform specialist at Eastern Michigan University in Ypsilanti, has been beta-testing the X4450 and plans to use it in a consolidation project to help cut data center power costs. “We want to get away from server sprawl,” he said. Sun officials said a full line of Intel-based systems will follow. But the company also plans to ship machines based on Advanced Micro Devices Inc.’s new Opteron quad-core chip by year’s end.