A Processor Designed in Europe Is Going Into the JUPITER Supercomputer
SiPearl has delivered the first samples of its Rhea1 processor to Bull, which has begun integrating them onto the BullSequana XH3000 platform for JUPITER, the European exascale supercomputer at Forschungszentrum Jülich in Germany. The two companies announced the delivery in a joint statement dated Sept. 22, 2026.
The chips are for JUPITER's CPU section, which will work alongside the graphics-processor partition the machine already has. JUPITER was procured by the EuroHPC Joint Undertaking. Thomas Lippert, director of the Jülich Supercomputing Centre, said of Rhea1 in the joint release: "Its high memory bandwidth is particularly well suited to applications that benefit from efficient access to large amounts of data."
On hardware, the release states that Rhea1 holds 80 Arm Neoverse V1 cores, four stacks of high-bandwidth memory and four DDR5 interfaces. It describes the chip as free of back doors and kill switches, which is the designers' account of their own part and not a tested finding. Rhea1 is due to be released at the end of 2026.
The companies say that performance testing is still running at SiPearl's laboratories, that the early data is strong and in some cases exceeds expectations, and that the figures have yet to be consolidated and will appear in the autumn of 2026. All of this (the "strong," the "exceeds expectations") is the two firms' own characterization, not an independently measured result.
The release says that Rhea1 will become the first European-designed CPU deployed in a European-built platform, and that the JUPITER equipment is SiPearl's first order for the chip and its first significant revenue. A second design, Rhea2, is intended for Alice Recoque, a French exascale machine.
