In announcing the move, the chip-making giant sent an e-mail to the press saying that its desktop motherboard business "will begin slowly ramping down over the course of the next three years." It added that the company's "internal talent and experience of twenty years in the boards business" is being reoriented toward "emerging new form factors."

After Haswell

Intel entered the motherboard-making business in 1993 to support its CPU business. In addition to Ultrabooks, smartphones and tablets, the new form factors include new all-in-ones and hybrid tablet/laptops.

The chip-making giant said that, following the release of boards using the fourth-generation Core processors known as Haswell, it will begin the phase-out. It will continue, however, to create form factor reference designs for desktops, as well as for tablets, Ultrabooks and other form factors, and manufacturers can then license designs from Intel. For instance, Gigabyte is offering Thin Mini-ITX motherboards for enthusiasts to build their own PCs, and the Gigabyte product will include standards for component computing developed by Intel.

But the definition of desktops is changing. In September, for instance, Intel showed off its Next Unit of Computing (NUC) at the 2012 Intel Developer Forum. It's a stripped-down PC with an Ivy Bridge CPU, motherboard, cooling assembly and, depending on whether it's a consumer or business version, either one or two HDMI connectors and either Ethernet or Thunderbolt -- all in a 4- by 4-inch package. Intel is working to get manufacturers interested in creating NUC-based, smaller and cheaper desktop computers.

'Around for a While'

While the big rollout of Windows 8 has led to a new wave of creative form factors, including seemingly acrobatic laptops whose screens swivel and flip into tablets, Microsoft has not been highlighting desktops. In 2008, sales of laptops exceeded those of desktops for the first time, and desktops, along with all PCs, have seen declining sales in recent years.

Intel has not indicated it will stop making the CPUs for desktops, only the motherboards. Motherboards contain the CPU, memory , and connectivity that represent the central components of a desktop computer. Industry observers expect that such companies as Asus, Gigabyte, MSI or Asrock will be happy to pick up the slack caused by Intel's gradual exit.

Ross Rubin, principal analyst at Reticle Research, said Intel's decision showed the company was "focusing its resources on mobility and energy efficient processors." He said desktops "will be around for a while," although he noted they are evolving into new kinds of all-in-ones, models containing lower-powered processors, and even models that can run for several hours on batteries, if needed.