HBM4
The high-bandwidth-memory generation with a 2048-bit interface and a logic base die. It has shipped since 2026 in Vera Rubin: 288 GB at 19.2 TB/s per GPU.
Current numbers
~288 GBShipping Rubin GPU: 288 GB HBM4 at 19.2 TB/s, flat from B300; H100 80 GB; Rubin Ultra announced 1 TB
432 GBMI455X per-accelerator HBM4 capacity: 432 GB
~8 → 19.2 TB/sPer-GPU HBM bandwidth, HBM3E (B200/B300) to HBM4 (shipping Vera Rubin, 8 stacks): ~2.4x