Nvidia Tests 192GB Rubin Ultra Variants With HBM4 as HBM4E Supply Strains
Updated
Updated · Tom's Hardware · Aug 10
Nvidia Tests 192GB Rubin Ultra Variants With HBM4 as HBM4E Supply Strains
3 articles · Updated · Tom's Hardware · Aug 10
Summary
Nvidia is reportedly evaluating at least three Rubin Ultra prototypes with 192 GB or 256 GB of memory, replacing the originally announced 1 TB HBM4E setup with lower-capacity HBM4 options.
HBM4E’s more complex customizable base logic die has strained supply, and memory makers reportedly cannot keep pace with Rubin Ultra demand, pushing Nvidia to explore fewer than the planned 16 memory stacks.
The changes would mark a sharp step down from expectations: Nvidia showed Rubin Ultra earlier this year as a four-chiplet compute tray with 1 TB of HBM4E, while current base Rubin GPUs ship with 288 GB of HBM4 each.
The testing also fits broader uncertainty around Rubin Ultra’s design and timing after June reports of a canceled quad-die version and a possible shift to dual-GPU models; Nvidia has said only that its roadmap remains intact.
HBM shortages extend beyond Nvidia: Samsung, SK hynix and Micron have reportedly sold through HBM capacity through 2027, and SK hynix’s CEO has called 2027 the worst year of a crunch that could last to 2030.