Samsung Electronics and SK hynix reportedly plan to mass-produce and ship 8Hi HBM4 to NVIDIA in Q2 2027, with 8-layer supply for Rubin Ultra and standard Rubin increasing as 12-layer production remains active. The reports attribute the shift to the greater cooling and yield challenges associated with taller DRAM stacks. Wccftech assessed the claim as “Questionable,” noting that NVIDIA has not finalized whether Rubin Ultra will use 8Hi HBM4, HBM4E, or a mixed configuration.