PC processor sales declined 8.3 percent in the first three months of the year compared to the last quarter of 2008, said Dean McCarron, principal of Mercury. "The quarter-on-quarter decline is only slightly worse than the average seasonal drop of 7.4 percent," McCarron said.

Notebook processors declined "far more" than desktop or server chips in the period. "Without the mobile downturn, the first quarter would have been much stronger than seasonal," he said.

AMD gained nearly four percentage points of market share over archrival Intel Corp. in the quarter. However, "the quarter was defined by inventory adjustments, so the statistics do not necessarily reflect the actual state of the market or market share," he added.

AMD had 20.9 percent of PC processor sales in the quarter, up from 17 percent in the fourth quarter of 2008, according to Mercury. Intel's share declined from 82.1 percent in the fourth quarter to 78.2 percent in the first three months of 2009.