Nvidia's next-generation Kyber rack-scale architecture, designed for its 2027 Rubin Ultra chips, has been delayed by more than 12 months to 2028 due to manufacturing difficulties with a key circuit board, according to research firm SemiAnalysis. The Kyber NVL144 rack architecture was delayed because the PCB midplane "remains challenging from a manufacturability standpoint," SemiAnalysis said in a post on Monday. The larger NVL576 system is also likely delayed or limited to small volumes. Nvidia rejected the report, stating, "Our roadmap is intact." Shares of Nvidia climbed about 1% on Monday. A backup plan to bolt two current-generation racks together was cancelled after cloud service providers and hyperscalers rejected the design due to its "odd design and heavy operational burden," SemiAnalysis said. The firm predicted this leaves Nvidia with "no proven solution to expand the scale-up world size for Rubin Ultra," potentially giving rivals Advanced Micro Devices and Google a technical opening.