The US government has refused to let Intel help China update the world's biggest supercomputer.
Intel applied for a licence to export tens of thousands of chips to update the Tianhe-2 computer.
The Department of Commerce refused, saying it was concerned about nuclear research being done with the machine.
Separately, Intel has signed a $200m (£136m) deal with the US government to build a massive supercomputer at one of its national laboratories.
The Tianhe-2 uses 80,000 Intel Xeon chips to generate a computational capacity of more than 33 petaflops. A petaflop is equal to about one quadrillion calculations per second.