AI tool comparison
GLM-5.1 vs GPT-5.5
Which one should you ship with? Here is the side-by-side panel verdict, pricing read, reviewer split, and community vote comparison.
AI Models
GLM-5.1
First open-source model to top SWE-bench Pro — 744B MoE, MIT, zero Nvidia
50%
Panel ship
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Community
Paid
Entry
GLM-5.1 is Z.ai's (formerly Zhipu AI) open-weight model released April 7, 2026 under the MIT license. It's a 744-billion-parameter Mixture-of-Experts architecture with 40 billion active parameters per token, a 200K-token context window, and a 131K maximum output length — and it became the first open-source model ever to lead SWE-bench Pro, scoring 58.4% versus Claude Opus 4.6's 57.3%. The training story is almost as remarkable as the performance. GLM-5.1 was trained entirely on approximately 100,000 Huawei Ascend 910B chips using the MindSpore framework — no Nvidia hardware was used at any point. That makes it one of the first frontier-tier models to demonstrate that the CUDA monoculture isn't technically mandatory for training state-of-the-art models. Z.ai became the first publicly traded foundation model company via a Hong Kong IPO in January 2026 (~$558M raised). The model is free to download from HuggingFace and also available via API at $0.95 per million input tokens. In agentic demonstrations, it has run autonomously for eight hours straight — 655 planning and execution iterations — without human checkpoints.
AI Models
GPT-5.5
OpenAI's new flagship unifies chat, code, and browser into one agent
75%
Panel ship
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Community
Free
Entry
OpenAI shipped GPT-5.5 on April 23, 2026, positioning it as "a major step toward a unified AI super-app" that combines chat, coding, and browser use in a single model. It is accessible via a new Agent Mode dropdown inside ChatGPT for Pro, Plus, and Team subscribers, and through the API for developers. The model delivers stronger tool use and reliability than its predecessors, with particular improvements in multi-step agentic task completion. New workspace agents for ChatGPT Business and Enterprise can autonomously handle tasks across Slack, Gmail, and other connected platforms — the same territory OpenAI has been building toward since the Agents SDK launch earlier this year. GPT-5.5 is OpenAI's answer to growing pressure from Anthropic's Claude Opus 4.7, Google's Gemini Enterprise platform, and open-source contenders like Kimi K2.6 and Arcee Trinity. Whether it actually leapfrogs the competition or merely matches it is still shaking out in independent benchmarks, but for the millions of existing ChatGPT users, it's the biggest capability jump they'll feel in day-to-day use this year.
Reviewer scorecard
“MIT license, top SWE-bench Pro score, $0.95/M via API. If your use case is agentic coding and you're not evaluating GLM-5.1, you're leaving real performance on the table. The 8-hour autonomous run capability is compelling for long-horizon task pipelines.”
“The API reliability improvements alone make this worth upgrading. Multi-step tool use has been the weak link in production OpenAI deployments — if GPT-5.5 actually fixes flakiness in function calling chains, that's worth the token cost increase.”
“SWE-bench Pro is one benchmark. The broader coding composite (Terminal-Bench 2.0 + NL2Repo) still has Claude Opus 4.6 ahead at 57.5 vs GLM-5.1's 54.9. Running 744B locally requires hardware most teams don't own, and the API's Chinese jurisdiction will trigger compliance blockers for many organizations.”
“OpenAI's release cadence has become so fast that GPT-5.5 may already feel dated by the time you integrate it. Independent benchmark results are inconsistent — some put it behind Kimi K2.6 on coding. And the 'unified super-app' framing is marketing; you're still paying separately for every capability.”
“The Huawei chip training story matters more than the benchmark ranking. If GLM-5.1 proves you can train frontier models without Nvidia at scale, it fractures the GPU supply chain narrative that's been shaping geopolitics and AI policy discussions for years. This is a proof of concept with enormous implications.”
“The Slack and Gmail workspace agents are the real story — they bring agentic AI to the office worker who will never touch an API. OpenAI's distribution advantage means GPT-5.5 will be the most-used AI model on the planet within weeks of launch, regardless of benchmark rankings.”
“For creative workflows, the 744B MoE overhead is overkill and local deployment requires datacenter-grade hardware that's nowhere near indie studio territory. The MIT license is great, but the gap between 'free to download' and 'free to actually run' is vast at this parameter count.”
“Agent Mode in ChatGPT is finally making AI feel less like a chatbot and more like a collaborator. For creators who live in a browser, having a model that can autonomously browse, research, and draft without constant hand-holding is a genuine time multiplier.”
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