GPT-5.6 Luna (Low) vs GPT-5.6 Terra (Xhigh)
Which is better for the money: GPT-5.6 Luna (Low) by OpenAI or GPT-5.6 Terra (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
GPT-5.6 Terra (Xhigh) scores 17.0 points higher (38.0 vs 21.0) but costs 44× as much to run the benchmark ($1187 vs $27.0; premium vs budget cost classes). They are not alternatives at one budget: pick GPT-5.6 Terra (Xhigh) when you need intelligence above 21.0, and GPT-5.6 Luna (Low) when 21.0 is enough.
| Metric | GPT-5.6 Luna (Low) | GPT-5.6 Terra (Xhigh) | Difference |
|---|---|---|---|
| Intelligence (higher is better) | 21.0 | 38.0 | +81.0% GPT-5.6 Terra (Xhigh) is 81.0% more intelligent |
| Total AA cost (lower is better) | $27.02 | $1,186.77 | +4292.2% GPT-5.6 Terra (Xhigh) is 44× more expensive |
| End-to-end time (lower is better) | 5.69s | 21.13s | +271.4% GPT-5.6 Terra (Xhigh) is 271.4% slower |
| Price per 1M tokens (in / out) | $0.20 / $1.20 | $2.00 / $12.0 | |
| Input modalities | Text, Image | Text, Image |
GPT-5.6 Terra (Xhigh) vs GPT-5.6 Luna (Low): 81.0% more intelligence, 4292.2% more cost to run the AA benchmark, and 271.4% slower end-to-end.
Today's Pareto frontier
Against the frontier
- GPT-5.6 Luna (Low) is off the frontier: at the same or lower cost, GPT-6 Luna (Low) scores 21.50 for $10.6.
- GPT-5.6 Terra (Xhigh) is off the frontier: at the same or lower cost, GPT-6.1 Sol (Max) scores 51.80 for $1082.
GPT-5.6 Luna (Low)GPT-5.6 Terra (Xhigh)Today's Pareto frontierEvery other model
Matchup
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Accept: text/markdown or ?format=md returns this page as Markdown. JSON: /api/v1/compare/gpt-5-6-luna-low/gpt-5-6-terra-xhigh · Markdown: /api/v1/compare/gpt-5-6-luna-low/gpt-5-6-terra-xhigh?format=md · llms.txt · agent skill