Leading designers of graphics processing units, Advanced Micro Devices and Nvidia Corp. have received subpoenas from the U.S. Department of Justice (DOJ) Antitrust Division in connection with the DOJ’s investigation into potential antitrust violations related to graphics processors and cards.

According to the most recent report from Jon Peddie Research, Intel Corp. was the largest supplier of PC graphics devices worldwide, and claimed an increased share of the total graphics market during the quarter with 40.3%. ATI remained the second largest supplier in Q2 with 27.6% of the market, whereas Nvidia was the third largest supplier of graphics devices in Q2 and commanded about 20.3% of the market. AMD entered the graphics processor business following the company’s acquisition of ATI Technologies earlier this year.

Intel Corp. ships only chipsets with built-in graphics cores, whereas AMD/ATI and Nvidia Corp. ship both chipsets with integrated graphics capabilities as well as graphics processing units used to produce add-in graphics cards. Intel did not reveal whether it had received a subpoena from the DOJ, while both AMD and Nvidia made appropriate statements on Friday.

The DOJ has not made any specific allegations against AMD/ATI or Nvidia. Both AMD and Nvidia Corp. intend to cooperate with the investigation.