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Stephen BJ
Stephen BJ

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RAG vs Fine-Tuning vs Alternatives

1. RAG (Retrieval-augmented generation)

Overview:

  • Combines retrieval and generation.
  • Retrieves relevant documents or chunks from a knowledge base.
  • The model then generates a response based on both the prompt and the retrieved content.

Cons:

  • Depends on retrieval quality.
  • Slightly higher latency.
  • Requires vector DB setup.

Use Cases:

  • Chatbots with knowledge bases.
  • Real-time support systems .

* Assistants with dynamic information.

2. Fine-Tuning

Overveiw:

  • Update model weights with domain or task-specific data.
  • Trains the model to behave specifically for your use case.

Types:

  • Full fine-tuning
  • Parameter-efficient (LoRA, QLoRA)

Cons:

  • Expensive in terms of compute.
  • Harder to update ( Need more GPU and datasets ).
  • Risk of overfitting.

Use Cases:

  • Legal or medical assistants
  • Summarization of company documents
  • Enterprise chat models

3. Alternatives to RAG and Fine-Tuning

3.1 Prompt Engineering

  • Design prompts to guide model behavior.
  • Use zero-shot or few-shot learning.

Pros:

  • Fast and low-cost
  • No retraining needed

Cons:

  • Limited in complexity and flexibility

3.2 Instruction-Tuned Models

  • Use LLMs already fine-tuned on instructions.
  • E.g., GPT-Instruct, Mistral-Instruct, Zephyr, LLaMA-2-chat

Pros:

  • High generalization
  • Works well with structured prompts

Cons:

  • Cannot customize deeply

Summary Table

Methods cost Setup complexity customization fresh knowledge Ideal For
RAG medium medium medium Yes Assistants, dynamic knowledge
Finetuning high high high No Specialized domain behavior
Prompt engineering Low very Low low Yes Lightweight domain tasks


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