The US DoJ (Department of Justice) has subpoenaed AMD as part of an antitrust investigation into the market for graphics processors and graphics cards, the firm said yesterday.

AMD recently entered the graphics chip business with its acquisition of ATI, which was finalised last month. The DoJ has not made any allegations against AMD or ATI, and AMD intends to co-operate with the investigation, it said.

While the DoJ hasn't said specifically what it is investigating, one industry analyst speculated that the case could be about price fixing. The DoJ has already charged a number of chip companies in the DRAM (Dynamic RAM) memory chip market for price fixing, and is investigating several in the SRAM (Static RAM) chip market.

"If the DoJ wanted to, it could just go down every line in the semiconductor industry and find the same issue," said Gartner analyst Richard Gordon. That's because there are a relatively few number of suppliers in the chip industry and an open flow of communication between competitors and customers, who may not define price fixing the same way the DoJ does, he said.

The investigations are unlikely to benefit end-users, according to Gordon. Historically, prices in the chip industry have gone up and down based on supply and demand and he doubts that such investigations will result in lower pricing.

A spokeswoman for AMD in Europe, Hollis Krym, said she did not know if the investigation has a broad scope and includes other graphics chip companies or if it is in the context of the ATI acquisition. US antitrust authorities have already approved AMD's merger with ATI.

In the DRAM market, the DoJ has charged Samsung, Hynix Semiconductor, Elpida Memory and Infineon Technologies with price fixing and sentenced the companies to pay multimillion-dollar fines.

Sony, Cypress Semiconductor and the US arms of Mitsubishi, Samsung and Toshiba have all been asked to turn over information to the DoJ for an investigation into SRAM price fixing.