Claude Fable 5.1 (High, Default Fallback) vs Claude Opus 5 (Low)
Which is better for the money: Claude Fable 5.1 (High, Default Fallback) by Anthropic or Claude Opus 5 (Low) by Anthropic? 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 Fable 5.1 (High, Default Fallbac… scores 11.8 points higher (51.2 vs 39.4) but costs 3.4× as much to run the benchmark ($5242 vs $1561; flagship vs premium cost classes). They are not alternatives at one budget: pick Claude Fable 5.1 (High, Default Fallbac… when you need intelligence above 39.4, and Claude Opus 5 (Low) when 39.4 is enough.
| Metric | Claude Fable 5.1 (High, Default Fallback) | Claude Opus 5 (Low) | Difference |
|---|---|---|---|
| Intelligence (higher is better) | 51.2 | 39.4 | −23.0% Claude Opus 5 (Low) is 23.0% less intelligent |
| Total AA cost (lower is better) | $5,241.59 | $1,560.91 | −70.2% Claude Opus 5 (Low) is 70.2% cheaper |
| End-to-end time (lower is better) | 28.41s | 11.28s | −60.3% Claude Opus 5 (Low) is 60.3% faster |
| Price per 1M tokens (in / out) | $10.0 / $50.0 | $5.00 / $25.0 | |
| Input modalities | Text, Image | Text, Image |
Claude Opus 5 (Low) vs Claude Fable 5.1 (High, Default Fallback): 23.0% less intelligence, 70.2% less cost to run the AA benchmark, and 60.3% faster end-to-end.
Today's Pareto frontier
Against the frontier
- Claude Fable 5.1 (High, Default Fallback) is off the frontier: at the same or lower cost, Claude Opus 5.5 (Xhigh, Default Fallback) scores 56.00 for $4057.
- Claude Opus 5 (Low) is off the frontier: at the same or lower cost, GPT-6.1 Sol (Max) scores 51.80 for $1082.
Claude Fable 5.1 (High, Default Fallback)Claude Opus 5 (Low)Today's Pareto frontierEvery other model
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