GPT-5.5-Pro vs GLM-4.6
OpenAI GPT-5.5-Pro | Z.ai GLM-4.6 | |
|---|---|---|
| Overview | ||
| Company | OpenAI | Z.ai |
| Release date | Apr 23 2026 | Sep 30 2025 |
| Access | Proprietary | Open Weight |
| Specifications | ||
Parameters | — | 355B |
Context window | — | 200k |
| Benchmarks | ||
Nonsense detection BullshitBench v2Given a confidently-worded but nonsensical prompt, does the AI spot that it makes no sense and push back — instead of playing along and inventing an answer? The score is how often it clearly called out the nonsense. Higher is better. | 36% | — |
Coding SWE-Bench VerifiedReal coding tasks pulled from open-source projects — the AI has to find and fix actual bugs. A human-checked version of the original SWE-Bench. Higher is better. | — | 68% |
Web browsing BrowseCompCan the AI browse the web and track down hard-to-find answers? Higher is better. | 90.1% | — |
Advanced math FrontierMath · Tier 1–3Very hard, research-level math problems. Tiers 1–3 are the (still extremely difficult) lower tiers. Higher is better. | 52.4% | — |
Advanced math FrontierMath · Tier 4Very hard, research-level math problems. Tier 4 is the hardest — close to what professional research mathematicians tackle. Higher is better. | 39.6% | — |
Knowledge work GDPval (win/tie rate)How often the AI's work matches or beats a human expert's on real knowledge-work tasks. Higher is better. | 82.3% | — |
| Timeline | ||
| Release gap | GLM-4.6 shipped 205 days before GPT-5.5-Pro | |
Which is better: GPT-5.5-Pro or GLM-4.6?
GPT-5.5-Pro and GLM-4.6 don't publish scores on any of the same benchmarks, so there's no direct head-to-head comparison. GLM-4.6 shipped 205 days before GPT-5.5-Pro, so benchmark comparisons should account for the intervening progress.
GPT-5.5-Pro is proprietary, while GLM-4.6 is open weight.
Direct benchmark comparisons are unavailable — GPT-5.5-Pro and GLM-4.6 don't publish scores on any of the same benchmarks.
Frequently asked questions
GPT-5.5-Pro was released by OpenAI on Apr 23 2026.
GLM-4.6 was released by Z.ai on Sep 30 2025.
GPT-5.5-Pro is a proprietary model released by OpenAI. GLM-4.6 is an open weight model released by Z.ai.
Other comparisons
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