New trade restrictions levied by the United States against China limit the sale of cutting-edge HPC and AI technologies from Nvidia and AMD to the world’s second-largest economy.

In an SEC filing, Nvidia revealed it was prohibited from exporting its A100 and forthcoming H100 GPUs to China and Russia, effective immediately. The stated purpose of the licensing requirements is to prevent “military end use” by these nations.

AMD reported it had also received instructions from U.S. authorities to halt sales of its top GPU chip, the Instinct MI250, to China and Russia. A variant of that chip, the MI250X, powers the U.S. Department of Energy’s Frontier supercomputer, which became the first officially ranked exascale supercomputer earlier this year.

The new export rules imposed on Nvidia apply to its entire lineup of A100 and H100 products and to systems that incorporate the technologies, including Nvidia’s own DGX systems and the HGX platforms used by a number of partner system-makers.

From Nvidia’s filing: “DGX or any other systems which incorporate A100 or H100 integrated circuits and the A100X are also covered by the new license requirement. The license requirement also includes any future Nvidia integrated circuit achieving both peak performance and chip-to-chip I/O performance equal to or greater than thresholds that are roughly equivalent to the A100, as well as any system that includes those circuits.”

In order to export the restricted technologies, Nvidia would need to apply for a license from the U.S. Commerce Department. According to a CNBC report, Nvidia is working closely with the U.S. government to manage the situation. 

Nvidia stated it is “engaging with customers in China” and “seeking to satisfy their planned or future purchases of the Company’s Data Center products with products not subject to the new license requirement.”

AMD, meanwhile, was told it cannot ship its MI250 accelerators to China and Russia. The company does not believe its MI100 chips are impacted. An AMD spokesperson, cited by Reuters, said the the new rules are not expected to have a material impact on the company’s business.

Rival chipmaker Nvidia, however, has more on the line. The company stands to lose $400 million in potential sales to China “if customers do not want to purchase the company’s alternative product offerings or if the [U.S. government] does not grant licenses in a timely manner or denies licenses to significant customers,” Nvidia stated in the recent SEC filing.

Nvidia said it will be permitted to continue H100 development projects in mainland China and Hong Kong. “The U.S. government has authorized exports, reexports, and in-country transfers needed to continue…development of H100 integrated circuits,” Nvidia reported in a separate SEC filing. “The authorization also allows the company to perform exports needed to provide support for U.S. customers of A100 through March 1, 2023. Additionally, the U.S. government authorized A100 and H100 order fulfillment and logistics through the company’s Hong Kong facility through September 1, 2023.”

China has condemned the move. Chinese foreign ministry official Wang Wenbin characterized the action as a “technological blockade” on China, and referred to it as “sci-tech hegemony.” “ The U.S. seeks to use its technological prowess as an advantage to hobble and suppress the development of emerging markets and developing countries,” he said in a statement.

The U.S. Commerce Department has not issued a formal announcement, but a spokesperson cited national security concerns. “While we are not in a position to outline specific policy changes at this time, we are taking a comprehensive approach to implement additional actions necessary related to technologies, end-uses, and end-users to protect U.S. national security and foreign policy interests,” the spokesperson said in a statement to Reuters.

While the new export rules apply to Russia as well as China, both Nvidia and AMD ceased doing business with Russia shortly after its invasion of Ukraine.

The action is the latest in a series of technology blocks levied by the U.S. against China. In 2015, Intel was denied an export license to supply its HPC processor technologies to a Chinese supercomputing project. The restriction notably induced China to significantly ramp up investments in so-called indigenous HPC technologies.

China also faces another U.S.-led export ban that restricts access to cutting-edge chipmaking technologies, such as extreme ultraviolet lithography, or EUV, used in the production of the most advanced <7nm computing nodes. Leading Chinese chipmaker Semiconductor Manufacturing International Corporation (SMIC) was able to develop 7nm process technology using older DUV machines.

China is currently home to two exascale supercomputers that were detailed as part of the Gordon Bell prize proceedings last year, but were not officially benchmarked for the Top500 list. The machines – made with all-Chinese technologies – purportedly produced Linpack scores on par with or above the United States’ exascale machine.

Nvidia stocks were down 7.7 percent Thursday, while AMD stocks ended the day down 3 percent.