GLM-5.1 (Reasoning) vs GPT-5.5 (High)
Which is better for the money: GLM-5.1 (Reasoning) by Z AI or GPT-5.5 (High) by OpenAI? Intelligence, total benchmark cost, and end-to-end time from Artificial Analysis & other sources, snapshot 2026-10-25.
Trade-off
Verdict
Depends on your budget
GPT-5.5 (High) scores 10.9 points higher (37.0 vs 26.1) but costs 2.3× as much to run the benchmark ($3411 vs $1487; flagship vs premium cost classes). Pick GPT-5.5 (High) when the extra intelligence is worth the premium, otherwise GLM-5.1 (Reasoning).
| Metric | GLM-5.1 (Reasoning) | GPT-5.5 (High) | Difference |
|---|---|---|---|
| Intelligence (higher is better) | 26.1 | 37.0 | +41.8% GPT-5.5 (High) is 41.8% more intelligent |
| Total AA cost (lower is better) | $1,486.78 | $3,410.76 | +129.4% GPT-5.5 (High) is 2.3× more expensive |
| End-to-end time (lower is better) | 64.38s | 19.56s | −69.6% GPT-5.5 (High) is 69.6% faster |
| Price per 1M tokens (in / out) | $1.28 / $4.07 | $5.00 / $30.0 | |
| Input modalities | Text | Text, Image |
GPT-5.5 (High) vs GLM-5.1 (Reasoning): 41.8% more intelligence, 129.4% more cost to run the AA benchmark, and 69.6% faster end-to-end.
Today's Pareto frontier
Against the frontier
- GLM-5.1 (Reasoning) is off the frontier: at the same or lower cost, GPT-6.1 Sol (Max) scores 51.80 for $1082.
- GPT-5.5 (High) is off the frontier: at the same or lower cost, Kimi K3.1 Pro scores 55.10 for $3117.
GLM-5.1 (Reasoning)GPT-5.5 (High)Today's Pareto frontierOpen-weights frontierEvery other model
Matchup
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Accept: text/markdown or ?format=md returns this page as Markdown. JSON: /api/v1/compare/glm-5-1/gpt-5-5-high · Markdown: /api/v1/compare/glm-5-1/gpt-5-5-high?format=md · llms.txt · agent skill