Claude Opus 5.5 (Xhigh, Default Fallback) vs GPT-5.6 Luna (Xhigh)
Which is better for the money: Claude Opus 5.5 (Xhigh, Default Fallback) by Anthropic or GPT-5.6 Luna (Xhigh) by OpenAI? Intelligence, total benchmark cost, and end-to-end time from Artificial Analysis & other sources, snapshot 2026-10-27.
Trade-off
Verdict
Depends on your budget
Claude Opus 5.5 (Xhigh, Default Fallbac… scores 21.4 points higher (56.0 vs 34.6) but costs 23× as much to run the benchmark ($4057 vs $179; flagship vs mid-range cost classes). They are not alternatives at one budget: pick Claude Opus 5.5 (Xhigh, Default Fallbac… when you need intelligence above 34.6, and GPT-5.6 Luna (Xhigh) when 34.6 is enough.
| Metric | Claude Opus 5.5 (Xhigh, Default Fallback) | GPT-5.6 Luna (Xhigh) | Difference |
|---|---|---|---|
| Intelligence (higher is better) | 56.0 | 34.6 | −38.2% GPT-5.6 Luna (Xhigh) is 38.2% less intelligent |
| Total AA cost (lower is better) | $4,056.65 | $179.33 | −95.6% GPT-5.6 Luna (Xhigh) is 95.6% cheaper |
| End-to-end time (lower is better) | 127.77s | 45.86s | −64.1% GPT-5.6 Luna (Xhigh) is 64.1% faster |
| Price per 1M tokens (in / out) | $4.00 / $20.0 | $0.20 / $1.20 | |
| Input modalities | Text, Image | Text, Image |
GPT-5.6 Luna (Xhigh) vs Claude Opus 5.5 (Xhigh, Default Fallback): 38.2% less intelligence, 95.6% less cost to run the AA benchmark, and 64.1% faster end-to-end.
Today's Pareto frontier
Against the frontier
- Claude Opus 5.5 (Xhigh, Default Fallback) is on today's frontier: nothing is both smarter and cheaper.
- GPT-5.6 Luna (Xhigh) is off the frontier: at the same or lower cost, GPT-6.1 Terra (Medium) scores 41.30 for $175.
Claude Opus 5.5 (Xhigh, Default Fallback)GPT-5.6 Luna (Xhigh)Today's Pareto frontierEvery other model
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