Bull says memory is now Europe's biggest missing link in supercomputing.

Bull CEO Emmanuel Le Roux told Reuters that the company now sources roughly 70% of its European-built supercomputer components locally, up from 20%-30% five years ago. Boards, interconnects, cooling and processors have advanced, while memory remains the major gap.

Samsung, SK Hynix and Micron produce more than 90% of the world's memory, Reuters noted. Le Roux said European memory initiatives exist but would take a long time to establish at scale.