Microprocessor unit shipments will decline by about 15 percent in 2009 compared to last year, according to preliminary numbers from the market researcher. Worldwide microprocessor shipments during the fourth quarter dropped 17 percent sequentially and 11.4 percent year-over-year, IDC said.

The research firm couldn't quantify the number of microprocessor shipped during the fourth quarter, but the fall was precipitous, said Shane Rau, research director at IDC.

"After hinting at a decline last September, the market fell of a cliff in October and November," Rau said.

The worldwide recession has slowed PC demand which will continue to affect microprocessor shipments. Worldwide PC shipments fell 0.4 percent year-over-year in the fourth quarter of 2008, IDC said in study released last month. Shipments of netbooks totaled 10 million in 2008, but strength in netbooks was outweighed by slow or even declining sales of traditional laptop and desktop PCs.

Intel took a big chunk of the server, mobile and desktop chip space from its rivals, Advanced Micro Devices and Via Technologies.