Even Intel can’t dictate the future. In a blog post on Friday, a Microsoft employee explained Microsoft’s plan to phase out support for Intel’s 64-bit Itanium CPU in favor of a 64-bit version of the nearly ubiquitous x86 chip.

Itanium, first released in 2001, was supposed to replace x86 with a radically different, higher-performance architecture meant for rack-mounted servers. Its 64-bit system architecture was supposed to obliterate 32-bit x86 chips in performance.

But Itanium never lived up to its promises and potential. Instead, x86 chips got faster and acquired 64-bit capability, nicknamed x64. Graphic processor units, or GPUs, took over much of the workload from x86 CPUs.

Customers stayed away from Itanium for three reasons: high price, dubious performance, and the much wider array of software available for x86 chips. (Hewlett-Packard’s HP-UX operating system is one of the few important platforms available for Itanium.)

Intel’s failure to capture new business from the start earned the chip the nickname “Itanic.” Yet until recently, Intel reserved some of its top performance features for Itanium instead of x86. Analyst Nik Simpson claimed in a blog post that Microsoft’s announcement was timed to Intel’s release of new multi-core Xeon 7500 chips, which bring former Itanium-only features to an x64 architecture. Microsoft and Intel have historically worked closely together, to the point where Microsoft allegedly¬†softened its requirements for PCs dubbed “Windows Vista Capable,” in order to let Intel sell its existing inventory of too-slow chips.

Today, Itanium could have been the power behind the cloud. Instead, the cloud is largely made up of x86 and x64 CPUs. Simpson wrote, “For Microsoft, reliability was the only thing that Itanium had going for it, the number of Windows licenses sold on Itanium is negligible compared to the x64 business. So the decision to drop Itanium was probably a relatively easy one.”

Intel said in February that it would launch the Itanium 9300 series of chips this year. Those chips have more than 2 billion transistors and are among the most complex chips ever designed. And last week, Intel server executive Kirk Skaugen said that Itanium was having great success attacking the $16 billion RISC computing market, dominated by IBM and Sun Microsystems. He said that the Itanium ecosystem — hardware, software and chips — was a $4 billion market. In that respect, he said that while Itanium is just 5 percent of the chip unit volume in servers, it is a much larger percentage of the revenue. But he acknowledged that the x86 Xeon chips were moving up into the “mission critical” computing space that was previously the domain of only the RISC and Itanium chips.