Inside Nvidia DGX A100: How Server PCBs Are Structured and Valued

The purpose of this article is to break down the composition of a server's PCB so readers can understand the real internal structure of a server and grasp the true value of upgrades.

1. Five major hardware sections: fan module, storage, GPU board, CPU motherboard, accessories

We focus on Nvidia DGX A100 as a benchmark AI server. The DGX A100 resembles a typical desktop case and can be divided into five hardware blocks.

1) Fan module: located at the front, consists of eight fans, similar to a traditional 8U server.

2) Storage: below the fan module are eight 3.84 TB drives, totaling 30 TB.

3) GPU board tray (rear): the core AI component, containing GPU modules, a carrier board, and NVSwitch.

4) CPU motherboard tray: core for all servers, includes CPU motherboard, system memory, NIC, and PCIe switch.

5) Power module: six power supplies at the rear, using thick‑copper PCBs.

From a functional perspective, PCB value can be grouped into three parts: GPU board, CPU motherboard, and the accessory modules (fan, storage, power).

2. GPU board group: single‑machine value ¥12,250, carrier board 52%, PCB 48%

The GPU board consists of four parts: GPU carrier board, NVSwitch, OAM (GPU accelerator card), and UBB (unit baseboard).

1) GPU carrier board: uses 70‑100 mm, 14‑16 layer FCBGA boards; 8 boards per DGX A100, each valued at about $100 (≈¥650), total ¥5,200.

2) NVSwitch: NVLink‑based module for GPU interconnect; each valued at $30 (≈¥195). With six switches per DGX A100, total ¥1,170.

3) OAM (GPU accelerator card): one‑to‑one with GPUs; eight per server. Area ≈0.03 m². High‑end version uses 20‑layer Ultra Low Loss CCL, priced ¥12,000/m²; PCIe version uses 14‑layer, priced ¥7,000/m². Estimated value per server ≈¥2,880.

4) UBB (unit baseboard): one per server, area ≈0.30 m², 26‑layer, Ultra Low Loss CCL, priced ¥10,000/m², giving ¥3,000 value.

Summing these, the GPU board occupies 0.624 m² of PCB area, valued at ¥12,250 (carrier board ¥6,370 ≈ 52%, PCB ¥5,880 ≈ 48%).

3. CPU motherboard group: single‑machine value ¥2,845, carrier board 46%, main board 40%

The CPU motherboard includes CPU carrier board, CPU main board, and functional sub‑boards (memory, NIC, expansion, storage driver).

1) CPU carrier board: similar to GPU carrier; two per server, each valued at $100 (≈¥650), total ¥1,300.

2) CPU main board: supports 64‑core AMD Rome CPU, PCIe 4.0, 10‑12 layer Low Loss CCL, area ≈0.38 m², priced ¥3,000/m², giving ¥1,140.

3) Functional sub‑boards: typically 8‑10 layer Mid Loss CCL, priced ¥1,500/m². Combined area ≈0.27 m², value ≈¥405.

CPU memory cards: 32 units, total 2 TB, each ≈0.004 m².

NICs: 10 cards (8×200 Gb/s IB, 2×200 Gb/s Ethernet), each ≈0.012 m².

Riser cards: one per server, ≈0.01 m².

Storage driver board: one board for two 1.92 TB NVMe drives, ≈0.01 m².

Total CPU motherboard PCB area is 0.662 m², valued at ¥2,845 (carrier board 46%, main board 40%, sub‑boards 14%).

4. Other accessories: single‑machine value ¥226

Includes power supplies, hard drives, and front console board. These use 6‑10 layer FR4/Mid Loss CCL, priced ¥1,000‑¥1,500/m².

1) Power supplies: six units, each PCB area ≈0.019 m².

2) Hard drives: eight 3.5" drives, each PCB area ≈0.008 m².

3) Front console board: one board, PCB area ≈0.010 m².

Summing GPU board, CPU motherboard, and accessories, the DGX A100 uses 1.474 m² of PCB, with a total value of ¥15,321. GPU board accounts for ¥12,000 (≈80%), CPU motherboard ¥2,845 (≈19%), and other accessories ¥226 (≈1%). At the board level, carrier boards contribute ¥7,670 (≈50.1%) and PCB boards ¥7,651 (≈49.9%).