GPT-5.5 (Xhigh) vs GPT-6 Luna (Non-reasoning)
Which is better for the money: GPT-5.5 (Xhigh) by OpenAI or GPT-6 Luna (Non-reasoning) 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
GPT-5.5 (Xhigh) scores 19.9 points higher (38.4 vs 18.5) but costs 276× as much to run the benchmark ($5294 vs $19.2; flagship vs budget cost classes). They are not alternatives at one budget: pick GPT-5.5 (Xhigh) when you need intelligence above 18.5, and GPT-6 Luna (Non-reasoning) when 18.5 is enough.
| Metric | GPT-5.5 (Xhigh) | GPT-6 Luna (Non-reasoning) | Difference |
|---|---|---|---|
| Intelligence (higher is better) | 38.4 | 18.5 | −51.8% GPT-6 Luna (Non-reaso… is 51.8% less intelligent |
| Total AA cost (lower is better) | $5,294.36 | $19.16 | −99.6% GPT-6 Luna (Non-reaso… is 99.6% cheaper |
| End-to-end time (lower is better) | 82.06s | 5.09s | −93.8% GPT-6 Luna (Non-reaso… is 93.8% faster |
| Price per 1M tokens (in / out) | $5.00 / $30.0 | $0.10 / $0.50 | |
| Input modalities | Text, Image | Text, Image |
GPT-6 Luna (Non-reasoning) vs GPT-5.5 (Xhigh): 51.8% less intelligence, 99.6% less cost to run the AA benchmark, and 93.8% faster end-to-end.
Today's Pareto frontier
Against the frontier
- GPT-5.5 (Xhigh) is off the frontier: at the same or lower cost, Claude Opus 5.5 (Xhigh, Default Fallback) scores 56.00 for $4057.
- GPT-6 Luna (Non-reasoning) is off the frontier: at the same or lower cost, GPT-6 Luna (Low) scores 21.50 for $10.6.
GPT-5.5 (Xhigh)GPT-6 Luna (Non-reasoning)Today's Pareto frontierEvery other model
Matchup
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