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We’re excited to announce that ChatGPT 5.1 is now available on Chat-O in the Power tier. This latest model from OpenAI brings enhanced reasoning, improved instruction following, and faster response times.
In our testing, ChatGPT 5.1’s performance has been really good and on par with state-of-the-art models. What stands out is how human it feels in conversation. The responses feel more natural, with better understanding of context and nuance. It handles complex reasoning tasks well and maintains consistency across longer conversations.
GPT-5.1 represents a significant mid-cycle improvement over GPT-5. Key upgrades include:
| Capability | GPT-5 | GPT-5.1 | Improvement |
|---|---|---|---|
| Reasoning depth | Strong | Deeper chain-of-thought | Noticeable on complex math/code |
| Instruction following | Good | Excellent | Fewer refusals, better adherence |
| Response naturalness | Natural | Near-human | More conversational flow |
| Context retention | 128K | 256K | Double the memory |
| Speed | Standard | 30% faster | Same quality, less waiting |
| Benchmark | GPT-5.1 Score | Previous Best |
|---|---|---|
| MMLU-Pro | 88.7% | 87.2% (GPT-5) |
| HumanEval | 91.8% | 89.5% (GPT-5) |
| GSM8K | 95.4% | 94.1% (GPT-5) |
| Arena Elo | 1352 | 1318 (GPT-5) |
While GPT-5.1 is excellent, the model landscape has evolved rapidly since its release. For specific tasks, newer specialized models may serve you better:
| Task | Better Model | Why |
|---|---|---|
| Deep reasoning | Kimi K3 | 2.8T param architecture, tops reasoning benchmarks |
| Long document analysis | GLM-5.2 | 1M token context window |
| Code generation | Kimi K2.7 Code | Purpose-built for end-to-end programming |
| Fast everyday tasks | GLM-5 Turbo | Optimized for fast inference |
| Balanced general use | GLM-5 | Great cost-to-performance ratio |
But here’s the key insight: you don’t have to choose. On Chat-O, you can use GPT-5.1 alongside all these models in the same conversation, switching as needed.
Complex Writing and Editing GPT-5.1’s natural language understanding makes it exceptional for long-form content creation, editing, and refinement. It maintains character voice and tone across lengthy documents better than most models.
Technical Documentation Its improved instruction following means it generates accurate, well-structured technical docs with minimal prompting.
Data Analysis and Interpretation GPT-5.1 handles structured data analysis well, identifying patterns and generating clear explanations of statistical results.
Multi-Turn Conversations The 256K context window and improved context retention make it ideal for extended back-and-forth sessions where you’re iterating on ideas.
You have two ways to access ChatGPT 5.1 on Chat-O:
Select “Advanced” mode and then choose OpenAI GPT 5.1 specifically from the model list. This gives you direct control, letting you use GPT 5.1 exclusively for your conversations. Perfect when you want to test the model directly or have a specific preference.
Stick to Power mode and GPT 5.1 will be part of the model fleet helping you automatically. In Power mode, our intelligent system selects the best model for each task, and GPT 5.1 is now part of that selection. This means you’ll benefit from GPT 5.1’s capabilities when it’s the right tool for the job, alongside other top-tier models.
| Tier | Models Available | Best For |
|---|---|---|
| Balanced | DeepSeek V3.2, GLM-5, Qwen QWQ 32B | Everyday tasks, quick answers |
| Power | GPT-5.1, Kimi K3, GLM-5.2, Claude Sonnet 4.6 | Complex reasoning, deep analysis |
Both options give you access to this powerful model. Advanced mode is ideal when you want to work with GPT 5.1 directly, while Power mode leverages it as part of an intelligent multi-model approach that adapts to your needs.
👉 Create an account or log in to try ChatGPT 5.1. New users receive 1,000 free credits to explore all our models.
Stay tuned for more model updates. We’re constantly adding the latest AI models to keep Chat-O at the cutting edge.