Fine-tuned Open-Source LLM Judge Outperforms GPT-5.2 at 15x Lower Cost

Jul 11, 2026

Together AI fine-tuned the open-source GPT-OSS 120B model using Direct Preference Optimization on 5,400 preference pairs. The resulting model outperformed GPT-5.2 in human preference alignment for evaluating model outputs, while offering 15x lower cost and 14x faster inference speeds.

Why it matters: This shows that open-source models can surpass proprietary models in specific evaluation tasks with significantly reduced cost and latency.

Full story at: Together AI Blog ↗