Claude Sonnet 5.5 (Xhigh, Default Fallback) vs GLM-5.1 (Reasoning)
Which is better for the money: Claude Sonnet 5.5 (Xhigh, 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 2026-10-26.
Trade-off
Verdict
Depends on your budget
Claude Sonnet 5.5 (Xhigh, Default Fallb… scores 25.8 points higher (51.9 vs 26.1) but costs 1.5× as much to run the benchmark ($2177 vs $1487; flagship vs premium cost classes). Pick Claude Sonnet 5.5 (Xhigh, Default Fallb… when the extra intelligence is worth the premium, otherwise GLM-5.1 (Reasoning).
| Metric | Claude Sonnet 5.5 (Xhigh, Default Fallback) | GLM-5.1 (Reasoning) | Difference |
|---|---|---|---|
| Intelligence (higher is better) | 51.9 | 26.1 | −49.7% GLM-5.1 (Reasoning) is 49.7% less intelligent |
| Total AA cost (lower is better) | $2,176.82 | $1,486.78 | −31.7% GLM-5.1 (Reasoning) is 31.7% cheaper |
| End-to-end time (lower is better) | 33.02s | 61.77s | +87.1% GLM-5.1 (Reasoning) is 87.1% slower |
| Price per 1M tokens (in / out) | $2.00 / $10.0 | $1.28 / $4.07 | |
| Input modalities | Text, Image | Text |
GLM-5.1 (Reasoning) vs Claude Sonnet 5.5 (Xhigh, Default Fallback): 49.7% less intelligence, 31.7% less cost to run the AA benchmark, and 87.1% slower end-to-end.
Today's Pareto frontier
Against the frontier
- Claude Sonnet 5.5 (Xhigh, Default Fallback) is off the frontier: at the same or lower cost, Claude Opus 5.5 (High, Default Fallback) scores 53.60 for $2172.
- 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 Sonnet 5.5 (Xhigh, Default Fallback)GLM-5.1 (Reasoning)Today's Pareto frontierOpen-weights frontierEvery other model
Matchup
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