HBM4 memory is now expected to reach volume production no earlier than the end of Q1 2026, according to a new report from TrendForce. The delay stems from two converging factors: Nvidia’s decision to revise its memory requirements upward for its next-gen Rubin GPU platform, and the company’s short-term strategy to aggressively extend shipments of its current Blackwell architecture. All three major HBM suppliers have been forced to redesign their HBM4 products to meet the new specifications, pushing mass manufacturing back by at least one quarter.
This shift keeps HBM3 and HBM3e as the prevailing standards across AI and high-performance GPU deployments through at least Q1 2026. Samsung may be first to qualify, given that it has reportedly passed Nvidia’s qualification tests, but SK hynix is still expected to maintain the majority share as the primary supplier to Nvidia. Micron, a more recent entrant in the HBM market, has already begun sampling 11 Gbps-class HBM4 parts, but is still building out volume readiness.
Nvidia delays HBM mass production
The changes also realign Nvidia’s internal cadence, with the Rubin GPU line, which will use HBM4 exclusively, now set for volume availability in the second half of 2026. Rubin’s target specs are the main reason HBM4 is behind schedule. According to TrendForce, Nvidia pushed for speeds higher than 11 Gbps per pin, which required all three vendors to retool their designs. Each HBM4 stack carries 2,048 data I/Os, so a 13 Gbps upgrade pushes aggregate per-stack bandwidth to over 2.6 TB/s. That level of throughput places new stress on base die logic and thermals.
SK hynix and Samsung began delivering engineering samples to Nvidia in late 2025, but with Nvidia demanding last-minute spec changes, those parts will now be insufficient for Rubin's requirements. Samsung is said to have a slight edge on qualification, due to its newer base die process and integration stack. Still, SK hynix is expected to retain the bulk of Nvidia’s business into 2026, given its existing allocation contracts.
(Image credit: Tom's Hardware)
This is not just about specs, however, but also Nvidia's broader control over memory ecosystems. Its sheer amount of purchasing power gives the company the leverage to shape JEDEC standards, dictate packaging needs, and pace supplier production cycles. NVIDIA accounts for over 60% of global HBM consumption in 2024, according to Morgan Stanley, and TSMC’s advanced packaging nodes — especially CoWoS — are already fully committed to Nvidia’s Blackwell and Grace Hopper-class parts. Moving to Rubin and HBM4 implies even greater substrate complexity, requiring further capacity expansion at both the foundry and substrate partner levels
Nvidia confirmed at CES that Rubin silicon is already in full production; however, system-level availability won’t follow until much later in the year, largely due to memory and interconnect bottlenecks. Rubin will ship with up to 288 GB of HBM4 and will rely on revised versions of Nvidia’s NVLink interconnect, optimized for the increased bandwidth profile. Early Rubin configurations are expected to pair with Grace CPUs via a refreshed NVLink architecture, allowing up to 900 GB/s of coherent bandwidth per link.
HBM suppliers recalibrate for 2026 volumes
The delay offers both a challenge and a reprieve for vendors. The challenge lies in redesigning HBM4 dies to meet Nvidia’s updated timing and signal integrity requirements, but the reprieve comes in the form of extra runway — most HBM3 and HBM3e nodes are now sold out through late 2026, and the additional time allows vendors to optimize yields and scale packaging operations.
... continue reading