Scaling LLMs – nano-GPT to GPT-3

LLM Architecture Series – Lesson 19 of 20. You now understand the core architecture. Scaling is about what happens when we make models wider, deeper, and train them on more data.

Surprisingly, performance often follows smooth scaling laws, which lets practitioners predict the benefit of using larger models.

Scaling LLMs annotated

Visualization from bbycroft.net/llm augmented by Nano Banana.

Scaling LLMs

Visualization from bbycroft.net/llm

The Same Architecture, Different Scales

The remarkable thing about transformer LLMs is that the architecture stays the same from tiny to massive. Only three things change: depth, width, and data.

Model Configurations

Model d_model Layers Heads Parameters
nano-gpt 48 3 3 85K
GPT-2 Small 768 12 12 117M
GPT-2 Medium 1024 24 16 345M
GPT-2 Large 1280 36 20 762M
GPT-2 XL 1600 48 25 1.5B
GPT-3 12288 96 96 175B

Scaling Laws

Research has shown predictable relationships:

Loss ∝ 1 / (Parameters)0.076

More parameters = better performance, following a power law.

Compute Scaling

Training cost scales roughly as:

  • Parameters × Tokens × 6 FLOPs
  • GPT-3 training: ~3.14 × 1023 FLOPs
  • Equivalent to thousands of GPU-years

Emergent Capabilities

Larger models don’t just do the same things better – they gain new abilities that smaller models lack entirely.

Series Navigation

Previous: Output Softmax

Next: The Complete LLM Pipeline


This article is part of the LLM Architecture Series. Interactive visualizations from bbycroft.net/llm.

Analogy and intuition

Scaling is like building a bigger library and hiring more librarians. With more books and more staff you can answer more complex questions, but you also pay higher costs.

Finding the right scale is about balancing capability, latency, and hardware budget for a given application.

Looking ahead

The final lesson will connect all steps into one clear pipeline from raw text input to generated output.

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