Shipments of processors during the third quarter went up by just 5 percent compared to the same quarter last year, according to Mercury Research. Chip shipments have grown despite flat-to-slow growth in PC shipments worldwide over the past year, said Dean McCarron, principal analyst at the research firm.

Intel held an 80.6 percent market share, a small drop from 80.3 percent market share during the third quarter last year. AMD's market share was 18.8 percent, growing from 18.3 percent market share last year.

Mercury Research's numbers cover all x86 systems including laptops, desktops and servers. The company did not provide full microprocessor shipment numbers.

AMD's Fusion mobile chips for netbooks and laptops are doing much better this year compared to last year, which helped the company gain year-over-year market share over Intel, McCarron said.

Fusion combines a powerful Radeon graphics core and CPU inside a single chip, and the processors are a giant upgrade over the previous generation of chips shipping last year. AMD's Fusion chips compete with Intel processors code-named Sandy Bridge, and both chips were released starting early this year.