Finland's New Supercomputer Roihu Enters Testing Phase
If the next four weeks pass without incident, the machine will be opened to all researchers in June
Text by Martti Asikainen, 16.5.2026 | Photo by CSC (Edited with AI)
Finland’s new supercomputer, Roihu, has entered its pilot phase, tripling the country’s national computing capacity and replacing two ageing machines. The procurement package, worth nearly €30 million, includes not only the supercomputer itself but also an overhaul of data management and cloud services.
CSC – IT Centre for Science launched Roihu’s pilot phase on 29 April, with 28 scientifically advanced and computationally demanding pilot projects now putting the new system through its paces using real workloads. During the four-week testing period, pilot users have access to Roihu’s full capacity. Should the pilot phase proceed without issues, the supercomputer will be opened to all users in June 2026.
Roihu is based on French company Eviden’s BullSequana XH3000 hybrid system and replaces CSC’s current national supercomputers, Mahti and Puhti. The machine is housed at CSC’s data centre in Kajaani, which is also home to the European LUMI supercomputer.
Three Times the Power of Its Predecessors
Roihu is capable of performing 49 petaflops — that is, 49 quadrillion calculations per second — tripling Finland’s national supercomputing resources.
The machine comprises 486 CPU nodes and 132 GPU nodes, along with specialist nodes for visualisation and high-memory requirements. Each CPU node is fitted with two 192-core AMD Turin 9965 processors, whilst the GPU nodes are equipped with four Nvidia GH200 Grace Hopper superchips.
The total value of the procurement package, including maintenance costs, comes to nearly €30 million. Alongside the supercomputer, the package covers an upgrade to Allas — the data management system serving all of Finland’s supercomputers — as well as additional GPU capacity for the Pouta cloud service. According to a study by Taloustutkimus, every euro invested in CSC’s high-performance computing services generated between €25 and €37 of societal benefit between 2018 and 2023.
AI, Drug Development and Climate Modelling
Roihu has been designed for broad scientific use. Researchers will be able to employ it for tasks ranging from analysing audio and video material and simulating molecular dynamics, to screening large libraries of potential drug compounds, studying glaciers and computing climate scenarios.
The supercomputer is particularly well suited to small and medium-sized artificial intelligence models, which represent the needs of the majority of researchers using CSC’s AI services. Roihu will also support machine learning on sensitive or confidential data.
The most computationally intensive tasks will continue to be handled by EuroHPC’s LUMI supercomputer, which has a theoretical peak performance of more than 531 petaflops and has ranked among the ten most powerful supercomputers in the world. Roihu’s role is to complement LUMI at the national level.
The contract for the delivery of Roihu was signed in November 2024, and pilot users were selected in February 2026.
