clm_c3e55dee4d704bc294442526b5d2fc0c_r1

VR2-0091

① SA Source

• Source: 開啟完整 SA 文章
• Section: Rubin
• Line hint: 125

Context Before

Transistor count has climbed 60% to 336 billion.

A notable omission from Rubin is the mention of Sparse FLOPs. In previous generations, 2:4 structured sparsity was used to double marketing FLOPs numbers. However, adoption was minimal especially at low precisions due to accuracy losses from the rigid sparsity structure forcing half of the values to be zero. Programmers basically ignored structured sparsity as it was not useful, which caused hardware designs to change as well. Blackwell Ultra GB300 added 50% more dense FP4 while keeping sparse FP4 FLOPs the same, while AMD’s MI355X stopped supporting structured sparsity on MXFP8, MXFP6 and MXFP4 formats to save silicon area.

Evidence

This is done automatically on existing models built for Blackwell without the need for a new programming model or specific optimizations

Context After

This means the sparser the workload, the closer the performance will be to the 50 PFLOPS marketed peak performance. NVIDIA thus brands the 50 PFLOPS figure as FP4 Inference while the 35 PFLOPS FP4 Training number is for dense workloads. As accuracy is preserved, this allows the marketing team to claim 5x FLOPs for Rubin over GB200, comparing 50 PFLOPS dynamically compressed FP4 to 10 PFLOPS dense FP4. Whether actual GEMM performance reaches 50 PFLOPS depends on how many zeros are in the tensor. The more zeros, the closer it can reach. The less zeros in the tensor, the lower the speedup. Overall, we expect to see much greater traction for Rubin’s adaptive sparsity compression as opposed to structured sparsity thanks to the automatic implementation.

With that said, many ML Systems engineer are still skeptical that this new form of sparsity will work well, and it is very possible that Nvidia’s 50 PFLOPS is purely marketing like prior generations

② Atomic Claim

此功能可自動套用在既有為 Blackwell 建立的模型上，不需要新的 programming model 或特定 optimizations。

• Epistemic Mode: ASSERTED
• Mapping Status: PARTIAL

③ Semantic Frame

{
  "attribute": "UNSPECIFIED_ATTRIBUTE",
  "context_nodes": [],
  "entity": {
    "id": "04_knowledge_base/Blackwell",
    "label": "Blackwell"
  },
  "frame_type": "ATTRIBUTE",
  "qualifiers": {
    "condition_text": null,
    "numeric_mentions": [],
    "temporal_mentions": []
  },
  "value": {
    "numeric_mentions": [],
    "value_text": "此功能可自動套用在既有為 Blackwell 建立的模型上，不需要新的 programming model 或特定 optimizations。"
  }
}

④ Canonical Entity Mapping

Role	Surface Label	Canonical Target
entity	Blackwell	Blackwell

⑤ Human Review

請在 Properties 逐項確認：

• 原文 → Atomic Claim 是否忠實
• Atomic Claim → Semantic Frame 是否忠實
• Canonical Entity mapping 是否正確
• Epistemic mode 是否保留原文語氣
• 最後選擇 review_action

Review state

Markdown 內文不是正式 approval。只有 Apply bridge 寫入的 Decision Ledger event 才是正式決策。