AMD CEO Dirk Meyer will step down after reaching an agreement with the company's board over his departure, AMD said today.

Former AMD CEO Dirk Meyer

Thomas Siefert, AMD's CFO, will fill Meyer's spot on a temporary basis as the company searches for a new CEO. It doesn't sound like the decision was entirely Meyer's.

"...the board believes we have the opportunity to create increased shareholder value over time. This will require the company to have significant growth, establish market leadership and generate superior financial returns. We believe a change in leadership at this time will accelerate the company's ability to accomplish these objectives," AMD said in a press release Monday.

Meyer had been with AMD since 1995, holding a variety of prominent engineering roles before becoming the man-in-waiting to succeed Hector Ruiz at the top spot, which he did in July 2008. During his tenure as CEO, AMD regained its financial footing to a certain degree, helped out by the settlement of its antitrust lawsuit against Intel for $1.25 billion in November 2009.

His departure comes as a bit of a surprise to the chip industry, judging by comments on Twitter from people like Microsoft's Rahul Sood, who worked closely with AMD for years developing gaming PCs for his Voodoo PC and later Hewlett-Packard, which acquired Sood's company. "woah...Dirk Meyer resigned from @amd. that was completely and totally unexpected...," he wrote.

AMD also announced preliminary revenue results for its fourth quarter, ahead of next week's expected announcement of its full financial results. Revenue will be $1.65 billion, slightly ahead of what analysts were expecting for the quarter.