Intel Corp. (NASDAQ:INTC), the No. 1 chipmaker, said it plans to phase out units that assemble the motherboards for PCs for some top customers to focus more on new designs for mobile platforms.

The announcement came after the Santa Clara, Calif.-based company reported a 27 percent slump in fourth-quarter earnings, and market researcher Gartner (NYSE:IT) said global PC shipments fell 3.5 percent in 2012.

Besides making all its own semiconductors, Intel for years has also used its global manufacturing network to put together the Core, Centrino and other microprocessors that it designs.

Some top customers, including Taiwan’s Asustek Computer (TPE:2357), often received these motherboards, which  were inserted into their own PCs and platforms. By 2016, a representative said, Intel plans to gradually phase out that business while keeping engineers working on new methods to deal with the ever-smaller forms for new chips.

Intel said it doesn’t plan to lay off any workers or engineers but will reassign them to working on these emerging projects. Intel employs nearly 105,000 people.

Shares of Intel fell a dime to $21.07 in Wednesday trading. They’ve gained more than 2 percent since Jan. 2.