Mixture-of-Experts (MoE) DeepSeek-v3

Image Interpretation: DeepSeek-v3 Mixture-of-Experts (MoE)

This image outlines the key technologies and performance efficiency of the DeepSeek-v3 model, which utilizes the Mixture-of-Experts (MoE) architecture. It is divided into the architecture diagram/cost table on the left and four key technical features on the right.

1. DeepSeekMoE Architecture (Left Diagram)

The diagram illustrates how the model processes data:

  • Separation of Experts: Unlike traditional MoEs, it distinguishes between Shared Experts (Green) and Routed Experts (Blue).
    • Shared Experts: Always active to handle common knowledge.
    • Routed Experts: Selectively activated by the Router to handle specific, specialized features.
  • Workflow: When an input (ut) arrives, the Router selects the top-$K$ experts (Top-Kr). The system processes the input through both shared and selected routed experts in parallel and combines the results.

2. Four Key Technical Features (Right Panel)

This section explains how DeepSeek-v3 overcomes the limitations of existing MoE models:

  • Load Balancing without Auxiliary Loss:
    • Problem: Standard MoEs often use “auxiliary loss” to balance expert usage, which can degrade performance.
    • Solution: It uses learnable bias terms in the router to ensure balance. This bias only affects “dispatching” (where data goes) and not the actual “weights” (calculation values), preserving model quality.
  • Shared Expert Design:
    • Concept: Keeping one or a few experts always active for general tasks allows the routed experts to focus purely on complex, specialized tasks.
    • Benefit: Reduces redundancy and improves the capacity utilization of experts.
  • Hardware-Aware Dual-Pipe Parallelism:
    • Efficiency: It fully overlaps All-to-All communication with computation, minimizing idle time.
    • Optimization: “Node-local expert routing” is used to minimize slow data transfers between different nodes.
  • FP8 Mixed-Precision Training:
    • Speed & Cost: Utilizes the tensor cores of modern GPUs (Hopper/Blackwell) for full FP8 (8-bit floating point) training. This drastically lowers both training and inference costs.

3. Cost Efficiency Comparison (Table 2)

The comparison highlights the massive efficiency gain over dense models:

  • DeepSeek-V3 MoE (671B parameters): Despite having the largest parameter count, its training cost is extremely low at 250 GFLOPS/Token.
  • LLaMa-405B Dense (405B parameters): Although smaller in size, it requires ~10x higher cost (2448 GFLOPS/Token) compared to DeepSeek-v3.
  • Conclusion: DeepSeek-v3 achieves “high performance at low cost” by massively scaling the model size (671B) while keeping the actual computation equivalent to a much smaller model.

Summary

  1. Hybrid Structure: DeepSeek-v3 separates “Shared Experts” for general knowledge and “Routed Experts” for specialized tasks to maximize efficiency.
  2. Optimized Training: It achieves high speed and balance using “Load Balancing without Auxiliary Loss” and “FP8 Mixed-Precision Training.”
  3. Extreme Efficiency: Despite a massive 671B parameter size, it offers roughly 10x lower training costs per token compared to similar dense models (like LLaMa-405B).

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With Gemini

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