Yi-1.5 34BvsGPT-o3
01.AI vs OpenAI — Side-by-side model comparison
Head-to-Head Comparison
| Metric | Yi-1.5 34B | GPT-o3 |
|---|---|---|
| Provider | ||
| Arena Rank | — | #2 |
| Context Window | 4K | 200K |
| Input Pricing | Free (open)/1M tokens | $2.00/1M tokens |
| Output Pricing | Free (open)/1M tokens | $8.00/1M tokens |
| Parameters | 34B | Undisclosed |
| Open Source | Yes | No |
| Best For | Bilingual tasks, fine-tuning, research | Advanced reasoning, agentic tasks, research |
| Release Date | May 13, 2024 | Apr 16, 2025 |
Yi-1.5 34B
Yi-1.5 34B is 01.AI's open-source model that delivers impressive performance for its size, particularly on bilingual Chinese-English tasks. At 34 billion parameters, it offers a strong foundation for fine-tuning and custom deployments. The Yi series has been influential in demonstrating that high-quality training data and methods can produce competitive models without requiring the largest compute budgets.
View 01.AI profile →GPT-o3
GPT-o3 is OpenAI's most advanced reasoning model, succeeding o1 as the frontier of deliberative AI. It uses an enhanced chain-of-thought approach where the model spends more compute time 'thinking' before responding, dramatically improving performance on complex STEM, mathematical, and logical reasoning tasks. With a 200K token context window and the ability to use tools during reasoning, o3 represents a significant leap in AI problem-solving capabilities. It achieved state-of-the-art results on the ARC-AGI benchmark, demonstrating near-human performance on novel reasoning challenges. The model is particularly strong at multi-step mathematical proofs, complex code debugging, and scientific analysis where careful step-by-step reasoning is essential. Originally priced at a premium, an 80% price reduction in June 2025 made o3 accessible to a much broader range of developers and applications.
View OpenAI profile →Key Differences: Yi-1.5 34B vs GPT-o3
GPT-o3 supports a larger context window (200K), allowing it to process longer documents in a single request.
Yi-1.5 34B is open-source (free to self-host and fine-tune) while GPT-o3 is proprietary (API-only access).
When to use Yi-1.5 34B
- +You need to self-host or fine-tune the model
- +Your use case involves bilingual tasks, fine-tuning, research
When to use GPT-o3
- +You need to process long documents (200K context)
- +You prefer a managed API without infrastructure overhead
- +Your use case involves advanced reasoning, agentic tasks, research
The Verdict
GPT-o3 wins our head-to-head comparison with 4 out of 5 category wins. It's the stronger choice for advanced reasoning, agentic tasks, research, though Yi-1.5 34B holds an edge in bilingual tasks, fine-tuning, research.
Last compared: March 2026 · Data sourced from public benchmarks and official pricing pages