DRAM supply shortage expected to persist through 2027; NVIDIA evaluates reducing HBM configuration on Rubin Ultra

Odaily News, Citrini analyst jukan posted on X platform, according to TrendForce's latest memory industry research, the DRAM supply shortage is expected to persist through 2027, and the HBM4e certification timeline remains uncertain. NVIDIA has been reassessing the HBM configuration for Rubin Ultra since the third quarter of 2026.

The original plan called for a 12-layer stacked HBM4e configuration, but NVIDIA is currently evaluating multiple designs in parallel, including HBM4e 8-layer stacking, HBM4 12-layer stacking, and HBM4 8-layer stacking, with the final specifications yet to be confirmed. In addition to NVIDIA, some CSPs are reportedly also considering reducing HBM capacity for their next-generation custom ASICs.

From 2025 to the first half of 2026, NVIDIA used 12-layer stacked HBM4e as the baseline design for Rubin Ultra. However, since the beginning of the third quarter of 2026, NVIDIA has begun reviewing lower-spec alternatives. TrendForce attributes this change to two major supply-side constraints: first, the overall DRAM shortage expected in 2027 will limit the wafer capacity that memory manufacturers can allocate to HBM production; second, uncertainty remains regarding the certification timeline for 12-layer stacked HBM4e and the pace of yield improvement in mass production.

TrendForce stated that NVIDIA's primary focus for the Rubin Ultra generation is improving I/O speed, with expanding GPU shipments as a secondary priority. If NVIDIA ultimately decides to downgrade the HBM specifications, it is expected to do so by reducing the number of DRAM stacking layers. Whether HBM4e can complete certification and enter mass production as planned will determine whether Rubin Ultra's I/O speed can be improved from the previous generation Rubin's 8 to 11.7Gbps to 14 to 16Gbps, or be maintained at 11 to 12Gbps through an optimized HBM4 design. Within the same product generation, the number of DRAM stacking layers determines the trade-off between HBM capacity per GPU and the number of GPUs that can be shipped.

TrendForce also believes that the final configuration will depend on wafer allocation decisions made by memory manufacturers. On the supply-demand front, HBM bit shipments in 2027 are expected to grow 50% to 60% year-over-year, but are still projected to fall short of demand growth. With supply constraints persisting, HBM suppliers are expected to maintain pricing power throughout 2027. The industry has broadly anticipated significant HBM price increases, and AI chip makers will face the dual pressure of limited HBM supply and rising procurement costs, further strengthening the incentive to adopt lower HBM capacity configurations.