The main families
GPT-4o (Omni)
A fast multimodal model: text, image, audio. Good for everyday chat, summarizing, light code and image analysis.
GPT-5
A new generation with better reasoning and instruction-following. For more complex tasks, long-form writing and professional projects.
The o series (o1, o3)
Reasoning models with an internal chain of thought. For math, logic, heavy code and multi-step problems.
Quick comparison table
| Model | Speed | Reasoning | Multimodal | هزینه |
|---|---|---|---|---|
| GPT-4o | High | Good | Yes | Medium |
| GPT-5 | Medium | Excellent | Yes | Higher |
| o3 | Lower | Excellent | Limited | High |
Which model for which task?
- Quick answers and chat: GPT-4o
- Reports and long-form content: GPT-5
- A math problem or algorithm: o3 or o1
- Image analysis: GPT-4o or GPT-5
Choosing in ChatQT
In the Chat In ChatQT you can change the model from the menu. PAYG means a more expensive model only costs when you use it. Details on the pricing.
Money-saving tips
- Start simple tasks with GPT-4o
- Only go to o3 for hard work
- Summarize long context
- Write a clear system prompt
You are a concise assistant. Answer in under 200 words unless I ask for detail.
Multimodal workflow
In one conversation: upload a screenshot of the error, have GPT-4o analyze it and suggest a fix — all in Chat ChatQT.
FAQ
Is GPT-5 always better? No; for simple questions, GPT-4o is faster and cheaper.
Who is o3 for? Developers, researchers and advanced math students.
Access in Iran
With Buy ChatGPT you access these models from ChatQT without a VPN. sign-up and topping up credit is enough.
API
Developers can use the ChatQT API for integration and choose the model on each request.
Conclusion
There's no single model for everything: GPT-4o for speed, GPT-5 for general quality, the o series for deep reasoning. ChatQT brings them all together in one app with Rial payment.