Chip developer Advanced Micro Devices (AMD) on Wednesday said it expected new US licensing requirements for semiconductors exported to China to cost it as much as US$800 million.

The Silicon Valley company's earnings warning, filed with the US Securities and Exchange Commission (SEC), came a day after rival Nvidia notified regulators that it expects a US$5.5 billion hit this quarter from licensing requirements on the main chip it can legally sell in China.

Shares in both companies were down by about seven percent at the close of formal trading on Wednesday.

The new US export control measure applies to MI308 graphics processing units (GPUs) designed for high-performance applications like gaming and artificial intelligence, AMD said.

AMD said in the filing that it expects to apply for export licences, but there is no assurance that they will be granted.

The US$800 million earnings blow it forecast would come from charges in "inventory, purchase commitments and related reserves," it added.

US officials last week told Nvidia it must obtain licences to export its H20 chips to China because of concerns they may be used in supercomputers there, the Silicon Valley company said in a SEC filing.

The United States had already restricted exports to China of Nvidia's most sophisticated GPUs, tailored for powering top-end artificial intelligence models.

Nvidia was told the licensing requirement on H20 chips would last indefinitely, it said in the filing. (AFP)