GPT-4o Audio vs GPT-3.5 Turbo

1. True multimodal audio model

• Accepts raw audio as input and produces audio or text as output.
• Enables hands-free, voice-first app experiences.

2. Natural real-time speech interaction

• Low-latency audio generation suitable for conversational agents.
• Great for voice assistants, phone bots, and interactive voice UI.

3. Large 128K context window

• Supports long conversations, call transcripts, instructions, or multi-part interactions.
• Ideal for building persistent voice agents or phone workflows.

4. High-output capacity

• Up to 16,384 max output tokens for extended responses or long explanations.
• Suitable for complex reasoning tasks in voice format.

5. Hybrid text + audio workloads

• Combine audio input/output with text prompts, instructions, or structured control.
• Useful for customer support bots, spoken form systems, IVR replacements, etc.

6. Compatible with the latest APIs

• Works with Chat Completions, Responses API, Realtime API, and Assistants.
• Supports streaming, function calling, and advanced developer tooling.

7. Strong performance for a preview model

• High reasoning and expression abilities relative to most audio-capable models.
• Designed for production-style experimentation prior to full release.

8. Ideal for next-gen voice applications

• Build lifelike AI agents, interview bots, tutoring systems, and spoken knowledge tools.
• Perfect for startups building audio-first user experiences.

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.