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.
Language Models
GLM-5.1
Open-weight #1 on SWE-bench Pro — built with zero Nvidia GPUs
100%
Panel ship
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Community
Paid
Entry
GLM-5.1 is a 744B Mixture-of-Experts model from Z.ai (formerly Zhipu AI) that achieved 58.4% on SWE-bench Pro—making it the first open-weight model to top the global coding benchmark leaderboard, edging out GPT-5.4 (57.7%) and Claude Opus 4.6 (57.3%). Available on HuggingFace under the MIT license, it's one of the most permissively licensed frontier-grade coding models that exists. The model runs with 40B active parameters despite its 744B total size, offers a 200K context window, and was refined specifically for coding and agentic tasks through reinforcement learning. The training story is remarkable: Z.ai has been on the US Entity List since January 2025, cutting off access to Nvidia data center GPUs entirely. The entire GLM-5 training run used approximately 100,000 Huawei Ascend 910B chips. For open-source practitioners, GLM-5.1 is a landmark: a frontier-class coding model with MIT weights and benchmark numbers that would have seemed impossible from a China-sanctioned lab a year ago. The hardware independence angle raises pointed questions about chip export control effectiveness—and suggests the Ascend 910B has become a genuinely competitive training platform at massive scale.
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
“The primitive here is a frontier-grade, MIT-licensed MoE coding model you can self-host — 40B active params at inference time despite 744B total weights, 200K context, no usage restrictions, no API keys before hello-world. The DX bet is correct: by releasing on HuggingFace under MIT, Z.ai put the complexity where it belongs — in your infra choices, not their licensing desk. SWE-bench Pro at 58.4% isn't a marketing claim; it's the same eval that humbled GPT-5 and Opus 4, and if you're running code agents in production today, the absence of a closed-API dependency is worth more than a 1% benchmark gap in either direction.”
“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.”
“Direct competitors are GPT-5 and Claude Opus 4 via API — both closed, both more expensive to run at scale, both with usage policies that can yank access. GLM-5.1 breaks at the infrastructure layer: you need serious hardware to serve 744B MoE at any latency that matters for interactive coding agents, and most teams don't have that. But the benchmark numbers are independently verifiable, the MIT license is unambiguous, and the Ascend 910B training story isn't PR spin — it's a geopolitical datapoint with real implications. What kills this in 12 months isn't a competitor; it's that cloud providers will offer managed endpoints and the 'open weights' story becomes theoretical for 90% of users. That said, the weights are real and the numbers are real, so: ship.”
“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 thesis this model bets on: chip export controls do not prevent frontier-class model training, and open-weight frontier models will become the infrastructure layer for commercial software development within 24 months. Both claims are now empirically stronger because of this release — 100,000 Ascend 910Bs producing a SWE-bench leader is the single most important data point on export control effectiveness since the controls were imposed. The second-order effect is the one that matters: if Huawei's Ascend stack is a credible frontier-training platform at scale, the assumption that Nvidia controls the ceiling of what's possible outside the US just broke. The open-weights + MIT license trend is on-time, not early — but GLM-5.1 is the first model to make that trend undeniable at coding-benchmark-frontier quality.”
“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.”
“The buyer for self-hosted GLM-5.1 is any team spending five figures monthly on closed coding-model APIs who also has compliance requirements that prohibit data leaving their infra — a real and growing cohort. Z.ai's actual moat isn't the weights (MIT means anyone can fine-tune and redistribute); it's that they've now proven they can train at this level without Nvidia, which means they're not blocked from the next iteration while US-sanctioned labs sit in hardware purgatory. The business risk is that MIT licensing is a distribution play, not a revenue play — Z.ai needs to convert open-weight credibility into enterprise API or cloud contracts fast, before the weights become a commodity that funds their competitors' fine-tunes.”
“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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