Claude 4.5 Sonnet (Reasoning) vs Claude Fable 5.1 (High, Default Fallback)
Which is better for the money: Claude 4.5 Sonnet (Reasoning) by Anthropic or Claude Fable 5.1 (High, Default Fallback) by Anthropic? Intelligence, total benchmark cost, and end-to-end time from Artificial Analysis & other sources, snapshot 2026-10-26.
Depends on your budget
Claude Fable 5.1 (High, Default Fallbac… scores 30.5 points higher (51.2 vs 20.7) but costs 3.5× as much to run the benchmark ($5242 vs $1501; 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 20.7, and Claude 4.5 Sonnet (Reasoning) when 20.7 is enough.
| Metric | Claude 4.5 Sonnet (Reasoning) | Claude Fable 5.1 (High, Default Fallback) | Difference |
|---|---|---|---|
| Intelligence (higher is better) | 20.7 | 51.2 | +147.3% Claude Fable 5.1 (Hig… is 2.5× more intelligent |
| Total AA cost (lower is better) | $1,501.22 | $5,241.59 | +249.2% Claude Fable 5.1 (Hig… is 3.5× more expensive |
| End-to-end time (lower is better) | 21.71s | 28.58s | +31.6% Claude Fable 5.1 (Hig… is 31.6% slower |
| Price per 1M tokens (in / out) | $3.00 / $15.0 | $10.0 / $50.0 | |
| Input modalities | Text, Image | Text, Image |
Claude Fable 5.1 (High, Default Fallback) vs Claude 4.5 Sonnet (Reasoning): 147.3% more intelligence, 249.2% more cost to run the AA benchmark, and 31.6% slower end-to-end.
Against the frontier
- Claude 4.5 Sonnet (Reasoning) 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) is off the frontier: at the same or lower cost, Claude Opus 5.5 (Xhigh, Default Fallback) scores 56.00 for $4057.
Compare something else
Accept: text/markdown or ?format=md returns this page as Markdown. JSON: /api/v1/compare/claude-4-5-sonnet-thinking/claude-fable-5-1-high · Markdown: /api/v1/compare/claude-4-5-sonnet-thinking/claude-fable-5-1-high?format=md · llms.txt · agent skill