Claude Opus 5.5 (Low, Default Fallback) vs GPT-6 Luna (Xhigh)
Which is better for the money: Claude Opus 5.5 (Low, Default Fallback) by Anthropic or GPT-6 Luna (Xhigh) by OpenAI? 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 Opus 5.5 (Low, Default Fallback) scores 7.7 points higher (42.3 vs 34.6) but costs 13× as much to run the benchmark ($860 vs $66.8; premium vs mid-range cost classes). They are not alternatives at one budget: pick Claude Opus 5.5 (Low, Default Fallback) when you need intelligence above 34.6, and GPT-6 Luna (Xhigh) when 34.6 is enough.
| Metric | Claude Opus 5.5 (Low, Default Fallback) | GPT-6 Luna (Xhigh) | Difference |
|---|---|---|---|
| Intelligence (higher is better) | 42.3 | 34.6 | −18.2% GPT-6 Luna (Xhigh) is 18.2% less intelligent |
| Total AA cost (lower is better) | $860.33 | $66.81 | −92.2% GPT-6 Luna (Xhigh) is 92.2% cheaper |
| End-to-end time (lower is better) | 16.52s | 31.80s | +92.5% GPT-6 Luna (Xhigh) is 92.5% slower |
| Price per 1M tokens (in / out) | $4.00 / $20.0 | $0.10 / $0.50 | |
| Input modalities | Text, Image | Text, Image |
GPT-6 Luna (Xhigh) vs Claude Opus 5.5 (Low, Default Fallback): 18.2% less intelligence, 92.2% less cost to run the AA benchmark, and 92.5% slower end-to-end.
Today's Pareto frontier
Against the frontier
- Claude Opus 5.5 (Low, Default Fallback) is off the frontier: at the same or lower cost, GPT-6.1 Sol (Xhigh) scores 51.00 for $662.
- GPT-6 Luna (Xhigh) is on today's frontier: nothing is both smarter and cheaper.
Claude Opus 5.5 (Low, Default Fallback)GPT-6 Luna (Xhigh)Today's Pareto frontierEvery other model
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