GPT-5.4 vs GPT-3.5 Turbo

1. Best Intelligence at Scale

• OpenAI positions GPT-5.4 as its frontier model for agentic, coding, and professional workflows.
• Built for complex professional work where stronger reasoning and higher answer quality matter.

2. Configurable Reasoning + Multimodal Input

• Supports configurable reasoning effort from none to xhigh, letting teams balance speed and depth.
• Accepts both text and image inputs while producing text output.

3. Massive Context for Long-Running Work

• 1.05M token context window supports very large codebases, documents, and multi-step workflows.
• Allows up to 128 k output tokens for long-form answers and larger generations.

4. Updated Knowledge & Broad Tool Support

• Knowledge cut-off of Aug 31 2025 keeps it current for newer frameworks and business context.
• Supports tools like web search, file search, code interpreter, hosted shell, computer use, and MCP in the Responses API.

1. Extremely low-cost text model

• One of the cheapest legacy models available.
• Suitable for very high-volume workloads with simple requirements.

2. Good for lightweight NLP tasks

• Classification, summarization, rewriting, paraphrasing, intent detection.
• Works for simple logic tasks and short reasoning sequences.

3. Works well for basic chatbots

• Optimized for Chat Completions API, originally powering early ChatGPT use cases.
• Good for rule-based or templated conversation flows.

4. Stable and predictable outputs

• Legacy behavior makes it suitable for systems built years ago that rely on its quirks.
• Good for backward compatibility or long-term enterprise pipelines.

5. Supports fine-tuning

• Useful for teams maintaining older fine-tuned GPT-3.5 models.
• Allows domain-specific compression of older datasets.

6. Limited capabilities compared to newer models

• No vision, no audio, no streaming, and no function calling.
• Much weaker reasoning and correctness vs GPT-4o mini or GPT-5.1.

7. Small context window (16K)

• Limited for multi-document tasks or long conversations.
• Best used for short, simple prompts or structured tasks.

8. Recommended migration path

• OpenAI explicitly recommends using GPT-4o mini instead.
• 4o mini is cheaper, smarter, faster, multimodal, and far more capable.