GLM-5.1 vs Claude vs GPT-6: Open-Source Model That Beats Frontier Models
GLM-5.1 is the first open-weight model to top SWE-Bench Pro, scoring 58.4 against GPT-5.4 (57.7) and Claude Opus 4.6 (57.3) — at API prices 5–10x lower than Anthropic’s flagship. It is not a universal winner, but for coding and agentic tasks, it has genuinely closed the gap with frontier closed models. What Is GLM-5.1? The Open-Weight Model That Shocked the Leaderboard GLM-5.1 is an open-weight large language model released by Zhipu AI (Z.ai) in April 2026, built on a 754-billion-parameter Mixture-of-Experts (MoE) architecture that activates only 40 billion parameters per token — the same efficiency design used by Mixtral and DeepSeek-V3. On April 7, 2026, GLM-5.1 became the first open-source model to claim the global #1 position on Scale AI’s SWE-Bench Pro leaderboard, scoring 58.4% against GPT-5.4 at 57.7% and Claude Opus 4.6 at 57.3%. That ranking held for 9 days before Claude Opus 4.7 reclaimed the top spot at 64.3%. The model ships under an MIT license, runs on vLLM and SGLang, supports a 200K-token context window with up to 128K output tokens, and was trained entirely on Huawei Ascend 910B chips — zero Nvidia GPU involvement. As of May 2026, it sits at #18 overall on Chatbot Arena and holds the #1 open-source model slot. For teams doing high-volume code generation or autonomous agent workflows, GLM-5.1 is the first open-weight option worth taking seriously against paid frontier APIs. ...
