Leak: OpenAI Asked Samsung for 4-Hi HBM Config but Was Rejected Amid Supply Constraints

zephyr_z9 · x · 2026-09-17

Leaker zephyrz9 claims the 4-Hi HBM stack configuration faces base-die supply constraints and resistance from memory makers, even though AI labs strongly favor it. According to the post, OpenAI asked Samsung for this config but was rejected for now.

He also does the math: holding one copy of model weights at fp4 requires 20TB of HBM. Using Huawei's hypothetical 4-Hi XPU (4GB × 4-Hi × 6 stacks = 96GB per accelerator), a 4096-accelerator scale-up node would carry over 384TB of HBM.

Related event: Rumor: Huawei to expand supernode to 4096 cards with 384TB HBM(2 posts)→

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