Yi-1.5 34BvsGPT-4o
01.AI vs OpenAI — Side-by-side model comparison
Head-to-Head Comparison
| Metric | Yi-1.5 34B | GPT-4o |
|---|---|---|
| Provider | ||
| Arena Rank | — | #2 |
| Context Window | 4K | 128K |
| Input Pricing | Free (open)/1M tokens | $2.50/1M tokens |
| Output Pricing | Free (open)/1M tokens | $10.00/1M tokens |
| Parameters | 34B | ~200B (est.) |
| Open Source | Yes | No |
| Best For | Bilingual tasks, fine-tuning, research | General purpose, coding, analysis |
| Release Date | May 13, 2024 | — |
Yi-1.5 34B
Yi-1.5 34B, developed by 01.AI, is an open-source model with 34 billion parameters and a 4K token context window delivering strong bilingual Chinese-English performance. The model handles general reasoning, content generation, and knowledge tasks competently, with particular attention to Chinese language understanding. Trained on a diverse multilingual corpus, Yi-1.5 34B performs well on both Chinese and English benchmarks while remaining deployable on standard enterprise GPU hardware. Free and open-source, it supports fine-tuning for domain-specific applications in Chinese enterprise environments. The model represents 01.AI's contribution to the open-source AI community, providing a capable bilingual foundation that researchers and developers can build upon. Yi-1.5 34B occupies a practical middle ground between smaller models and frontier-scale systems for organizations needing Chinese-English AI capabilities.
View 01.AI profile →GPT-4o
GPT-4o is OpenAI's flagship multimodal model, capable of processing text, images, and audio in a unified architecture. The 'o' stands for 'omni,' reflecting its ability to seamlessly handle multiple input types. With a 128K token context window and competitive pricing, it strikes an optimal balance between capability and cost-effectiveness. GPT-4o delivers fast response times while maintaining strong performance across coding, analysis, creative writing, and visual understanding tasks. It powers ChatGPT's default experience and is one of the most widely deployed AI models globally, serving millions of API calls daily. The model supports function calling, JSON mode, and structured outputs, making it highly versatile for production applications. Its combination of speed, quality, and multimodal capabilities makes it the go-to choice for most general-purpose AI applications.
View OpenAI profile →Key Differences: Yi-1.5 34B vs GPT-4o
GPT-4o supports a larger context window (128K), 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-4o is proprietary (API-only access).
Yi-1.5 34B has 34B parameters vs GPT-4o's ~200B (est.), which affects inference speed and capability.
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-4o
- +You need to process long documents (128K context)
- +You prefer a managed API without infrastructure overhead
- +Your use case involves general purpose, coding, analysis
The Verdict
GPT-4o wins our head-to-head comparison with 5 out of 5 category wins. It's the stronger choice for general purpose, coding, analysis, though Yi-1.5 34B holds an edge in bilingual tasks, fine-tuning, research.
Last compared: April 2026 · Data sourced from public benchmarks and official pricing pages