Infatuated with Itanium, Intel has long resisted the obvious: creating a 64-bit chip that simply extends the x86 architecture on which the company built its fortune. Instead, Intel has ceded that ground to AMD, whose 64-bit, x86-compatible Opteron has steadily eaten into the market shares of both Itanium and the 32-bit Xeon throughout the past year. For many, Itanium has been too expensive and too much of a departure. And Xeon has lacked the 64-bit headroom provided by Opteron.
The game changed in late June when Intel introduced its newest Xeon processor, code-named Nocona. Intel unveiled the most recent arrival in its storied Xeon processor line with little fanfare, but in fact, it's a major departure given that Intel has actually adapted the x86-64 instruction set that AMD developed for the Opteron. Intel's new architecture, the EM64T (Extended Memory 64 Technology), brings a Xeon chip into direct competition with the Opteron for the first time.
News source: InfoWorld