The FTC's latest suit was filed a month after Intel agreed to pay $1.25 billion to settle antitrust complaints brought against it by AMD. The smaller chip maker had accused Intel of similar tactics to those in the FTC complaint, saying Intel provided rebates to PC makers if they agreed to forgo the use of AMD chips.
Intel admitted to no wrongdoing in that settlement. But it was also sued by the European Commission, which last May found Intel guilty of abusing its dominant position to shut smaller rivals out the market. It fined Intel €1.06 billion ($1.45 billion at the time), the biggest fine it had imposed in its history. Intel is appealing that decision.
Most of the previous cases dealt with CPUs only, but the FTC was also troubled by Intel's conduct in the graphics market. General purpose GPU chips from companies like Nvidia and AMD's ATI division are taking on CPU-like capabilities and are therefore another threat to Intel's dominance, the FTC said in its complaint.
It accused Intel of several illegal tactics to hamper the development of its rivals' GPUs, including denying interoperability with its own microprocessors, and selling its CPUs and GPUs bundled together at below cost.
Intel and Nvidia filed opposing lawsuits last year over the interoperability issue, and the case is scheduled for trial in September.
Intel has maintained a 75 to 85 percent share of the desktop and server CPU markets for the past decade, the FTC said, giving it monopoly power. Research firm IDC said Intel's share of the PC chip market in the first quarter this year was 81 percent, compared to 18.8 percent for AMD and 0.2 percent for VIa.
Intel's share of the GPU market is more than 50 percent, the FTC said.