Claude Fable 5.1 (Medium, Default Fallback) vs GPT-6 Luna (Medium)
Which is better for the money: Claude Fable 5.1 (Medium, Default Fallback) by Anthropic or GPT-6 Luna (Medium) by OpenAI? Intelligence, total benchmark cost, and end-to-end time from Artificial Analysis & other sources, snapshot 2026-10-24.
Trade-off
Verdict
Depends on your budget
Claude Fable 5.1 (Medium, Default Fallb… scores 19.0 points higher (48.9 vs 29.9) but costs 128× as much to run the benchmark ($3983 vs $31.2; flagship vs budget cost classes). They are not alternatives at one budget: pick Claude Fable 5.1 (Medium, Default Fallb… when you need intelligence above 29.9, and GPT-6 Luna (Medium) when 29.9 is enough.
| Metric | Claude Fable 5.1 (Medium, Default Fallback) | GPT-6 Luna (Medium) | Difference |
|---|---|---|---|
| Intelligence (higher is better) | 48.9 | 29.9 | −38.9% GPT-6 Luna (Medium) is 38.9% less intelligent |
| Total AA cost (lower is better) | $3,983.28 | $31.17 | −99.2% GPT-6 Luna (Medium) is 99.2% cheaper |
| End-to-end time (lower is better) | 13.16s | 8.25s | −37.3% GPT-6 Luna (Medium) is 37.3% faster |
| Price per 1M tokens (in / out) | $10.0 / $50.0 | $0.10 / $0.50 | |
| Input modalities | Text, Image | Text, Image |
GPT-6 Luna (Medium) vs Claude Fable 5.1 (Medium, Default Fallback): 38.9% less intelligence, 99.2% less cost to run the AA benchmark, and 37.3% faster end-to-end.
Today's Pareto frontier
Against the frontier
- Claude Fable 5.1 (Medium, Default Fallback) is off the frontier: at the same or lower cost, Kimi K3.1 Pro scores 55.10 for $3117.
- GPT-6 Luna (Medium) is on today's frontier: nothing is both smarter and cheaper.
Claude Fable 5.1 (Medium, Default Fallback)GPT-6 Luna (Medium)Today's Pareto frontierEvery other model
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