In addition to the AMD probe, the FTC has approached Nvidia about Intel's business practices. This time in the graphics chip market, according to sources familiar with the matter. An Nvidia spokesperson would not comment. The Nvidia-related probe was reported by BusinessWeek.

Intel commands about 50 percent of the graphics chip market. Though Nvidia is the world's leading supplier of "discrete," or standalone, graphics chips, it ranks a distant second in overall market share to Intel, which supplies "integrated" graphics built into the chipsets that accompany all of its processors. Mercury Research estimates the total market for graphics chips, including integrated graphics, at almost $10 billion in 2009.

In the third quarter, Intel had 53 percent of the graphics chip market, up from the 49 percent share in the same period last year, according to Jon Peddie Research, which tracks the graphics chip market. Nvidia took about 24 percent, down from the 28 percent in the third quarter of last year.

Nvidia claims that Intel's "bundling" tactics, the same tactics that AMD has cited for years and that were spelled out in a complaint filed by New York's attorney general last month, are causing it undue harm.