GLM-5.2 vs GPT-5.5 Pro
Verdict
GPT-5.5 Pro leads 9–0 across 9 shared benchmarks.
GLM-5.2 0 · GPT-5.5 Pro 9 · higher isn't always better — see caveats.
Per-benchmark head-to-head
Reported scores — protocols may differ. How we compare
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GLM-5.2GPT-5.5 Pro
Capabilities
Reasoning
Reasoning: GPT-5.5 Pro leads 3–0 across 3 shared reasoning benchmarks (largest gap: SimpleQA Verified, 64.5 vs 38.1 — single evaluator).
4 reproduced2 unverified
Math
Math: GPT-5.5 Pro leads 2–0 across 2 shared math benchmarks (largest gap: FrontierMath-Tier-4-v2-Private, 78.05 vs 29.27 — single evaluator).
4 reproduced
What the labs claim
Vendor claims — compare against the measured scores above. A claim is what a developer says about its own model, not an independent measurement.
GLM-5.2
Coding
“Advanced Coding with Flexible Effort: Stronger coding capabilities with multiple thinking effort levels to balance performance and latency”
huggingface.co2026
Context Handling
“We propose IndexShare, which reuses the same indexer across every four sparse attention layers, reducing per-token FLOPs by 2.9x at a 1M context length.”
huggingface.co2026
General
“Pure Open: An MIT open-source license - no regional limits, technical access without borders”
huggingface.co2026
GPT-5.5 Pro
General
“In GPT-5.5 Pro, early testers are seeing a significant step up in both the difficulty and quality of work ChatGPT can take on”
openai.com2026
Reasoning
“GPT-5.5 Pro, designed for even harder questions and higher-accuracy work, is available to Pro, Business, and Enterprise users.”
openai.com2026
Writing
“testers found GPT-5.5 Pro's responses significantly more comprehensive, well-structured, accurate, relevant, and useful”
openai.com2026