Claude Opus 5.5 (High, Default Fallback) vs GLM-5.1 (Reasoning)
Which is better for the money: Claude Opus 5.5 (High, Default Fallback) by Anthropic or GLM-5.1 (Reasoning) by Z AI? 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
Claude Opus 5.5 (High, Default Fallback) scores 27.5 points higher (53.6 vs 26.1) but costs 1.5× as much to run the benchmark ($2172 vs $1487; flagship vs premium cost classes). Pick Claude Opus 5.5 (High, Default Fallback) when the extra intelligence is worth the premium, otherwise GLM-5.1 (Reasoning).
| Metric | Claude Opus 5.5 (High, Default Fallback) | GLM-5.1 (Reasoning) | Difference |
|---|---|---|---|
| Intelligence (higher is better) | 53.6 | 26.1 | −51.3% GLM-5.1 (Reasoning) is 51.3% less intelligent |
| Total AA cost (lower is better) | $2,172.43 | $1,486.78 | −31.6% GLM-5.1 (Reasoning) is 31.6% cheaper |
| End-to-end time (lower is better) | 36.54s | 64.38s | +76.2% GLM-5.1 (Reasoning) is 76.2% slower |
| Price per 1M tokens (in / out) | $4.00 / $20.0 | $1.28 / $4.07 | |
| Input modalities | Text, Image | Text |
GLM-5.1 (Reasoning) vs Claude Opus 5.5 (High, Default Fallback): 51.3% less intelligence, 31.6% less cost to run the AA benchmark, and 76.2% slower end-to-end.
Today's Pareto frontier
Against the frontier
- Claude Opus 5.5 (High, Default Fallback) is on today's frontier: nothing is both smarter and cheaper.
- GLM-5.1 (Reasoning) is off the frontier: at the same or lower cost, GPT-6.1 Sol (Max) scores 51.80 for $1082.
Claude Opus 5.5 (High, Default Fallback)GLM-5.1 (Reasoning)Today's Pareto frontierOpen-weights frontierEvery other model
Matchup
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