LUMI AI Supercomputer Data Center

LUMI resides in a repurposed paper mill in Kajaani, Finland, where abundant hydroelectric power and direct liquid cooling enable one of the world’s fastest and greenest supercomputers. The HPE Cray EX system packs 10,240 AMD Instinct MI250X GPUs and high-memory CPU partitions connected by Slingshot-11 networking, sustaining 379.5 petaflops on LINPACK and over an exaflop of AI throughput. Warm-water cooling captures waste heat for the local district heating network, yielding an effective PUE near 1.04 while powering European research into climate digital twins, biosciences, and large-scale AI models.

LUMI is the pre-exascale flagship of EuroHPC JU (European High Performance Computing Joint Undertaking), a multi-country initiative established in 2018 to give European researchers access to world-class HPC and AI compute without dependence on US cloud providers. CSC — IT Center for Science operates the system on behalf of a ten-country consortium: Finland, Belgium, Czech Republic, Denmark, Estonia, Iceland, Norway, Poland, Sweden, and Switzerland. EuroHPC JU co-funds the infrastructure alongside the member countries. When LUMI entered full production in June 2022, it ranked third on the TOP500 list of the world’s most powerful supercomputers — the highest-ranked system outside the United States and Japan at the time.

The GPU-accelerated partition drives growing demand for large language model training and multimodal AI research. European universities, national research institutes, and government agencies access LUMI through competitive EuroHPC JU project calls and national share allocations. Published workloads include climate and weather modeling, drug discovery, cosmological simulations, and training AI models at a scale that would otherwise require access to commercial hyperscaler GPU clusters. The system gives European researchers a compute resource that operates under European data governance, without routing sensitive research through US or Asian cloud infrastructure.

On sustainability: Kajaani’s hydroelectric grid provides near-zero-carbon power with high availability year-round. LUMI’s direct liquid cooling system transfers waste heat directly into the city’s district heating network, an unusually complete energy loop where the heat generated by AI training reduces fossil fuel consumption for local residents and businesses.