clm_eda586b437ac4b228332210dfeda4acb_r1

VR2-0149

① SA Source

• Source: 開啟完整 SA 文章
• Section: Rubin Oberon Rack: NVL72 not NVL144 nor NVL36
• Line hint: 185

Context Before

While not part of the Rubin NVL72 rack, Spectrum-6 CPO enables even larger scale-out clusters with its doubled radix. The design retains the same features as Spectrum-5, with 8 IO chiplets surrounding the main switch die. 102.4T switching bandwidth is achieved with 512x 200G SerDes. 32 3.2T optical engines on the package convert these electrical signals to optical links, each with a detachable fiber connector. The SN6810 features one of these chips, while the SN6800 houses four, multiplexed together to create a 409.6T switch box. There will also be a non-CPO version with pluggable OSFP cages in the SN6600. The non-CPO version will be more common in our view.

Rubin Oberon Rack: NVL72 not NVL144 nor NVL36

Evidence

Since the announcement of GB200 at Nvidia GTC 2024, the concept of an AI server system has shifted from a chassis to a rack scale system. In our GB200 article ↗, we discussed the evolution of Nvidia AI server form factor from HGX (8 GPU per node) to Oberon (NVL72 rack scale). While the HGX form factor still exists, the majority of Nvidia’s Blackwell GPUs are integrated in the Oberon form factor. Rubin will also be offered in both HGX and Oberon systems.

Context After

The key difference between the Blackwell and Rubin Oberon architecture is the number of SKUs offered to customers. As Blackwell Oberon was the first ever mass deployment of a rack scale solution with rack power density over 100KW for the GB200 NVL72 SKU, many datacenters did not have the infrastructure ready to support 100kw+ per rack. Nvidia offered two SKUs of Blackwell Oberon: GB200 NVL72 and GB200 NVL36x2. The latter being a lower density SKU offered for customers who did not have the infra ready to handle the thermals of a single high density rack. We discussed the difference between the two form factors in the GB200 article ↗. ↗

Unlike Blackwell, Rubin is only offered in the VR NVL72 SKU. The set up is very similar to that of GB200/GB300 NVL72. Each VR NVL72 system consists of:

② Atomic Claim

在 GB200 文章中，SemiAnalysis 說明 Nvidia AI server form factor 從 HGX（每 node 8 顆 GPU）演進到 Oberon（NVL72 rack scale）。

• Epistemic Mode: ASSERTED
• Mapping Status: COMPLETE

③ Semantic Frame

{
  "attribute": "COUNT",
  "context_nodes": [
    {
      "id": "02_companies/NVDA",
      "label": "Nvidia"
    },
    {
      "id": "04_knowledge_base/HGX",
      "label": "HGX"
    },
    {
      "id": "04_knowledge_base/GPU",
      "label": "GPU"
    },
    {
      "id": "04_knowledge_base/NVIDIA Oberon",
      "label": "Oberon"
    }
  ],
  "entity": {
    "id": "04_knowledge_base/GB200",
    "label": "GB200"
  },
  "frame_type": "ATTRIBUTE",
  "qualifiers": {
    "condition_text": null,
    "numeric_mentions": [
      "8"
    ],
    "temporal_mentions": []
  },
  "value": {
    "numeric_mentions": [
      "8"
    ],
    "value_text": "在 GB200 文章中，SemiAnalysis 說明 Nvidia AI server form factor 從 HGX（每 node 8 顆 GPU）演進到 Oberon（NVL72 rack scale）。"
  }
}

④ Canonical Entity Mapping

Role	Surface Label	Canonical Target
entity	GB200	GB200
context_0	Nvidia	NVDA
context_1	HGX	HGX
context_2	GPU	GPU
context_3	Oberon	04_knowledge_base/NVIDIA Oberon

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。