GPT-5.6 Luna (Xhigh) vs gpt-oss-20b (High)
Which is better for the money: GPT-5.6 Luna (Xhigh) by OpenAI or gpt-oss-20b (High) 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-5.6 Luna (Xhigh) scores 25.6 points higher (34.6 vs 9.0) but costs 6.2× as much to run the benchmark ($179 vs $28.8; mid-range vs budget cost classes). They are not alternatives at one budget: pick GPT-5.6 Luna (Xhigh) when you need intelligence above 9.0, and gpt-oss-20b (High) when 9.0 is enough.
| Metric | GPT-5.6 Luna (Xhigh) | gpt-oss-20b (High) | Difference |
|---|---|---|---|
| Intelligence (higher is better) | 34.6 | 9.0 | −74.0% gpt-oss-20b (High) is 74.0% less intelligent |
| Total AA cost (lower is better) | $179.33 | $28.81 | −83.9% gpt-oss-20b (High) is 83.9% cheaper |
| End-to-end time (lower is better) | 45.80s | 13.96s | −69.5% gpt-oss-20b (High) is 69.5% faster |
| Price per 1M tokens (in / out) | $0.20 / $1.20 | $0.05 / $0.22 | |
| Input modalities | Text, Image | Text |
gpt-oss-20b (High) vs GPT-5.6 Luna (Xhigh): 74.0% less intelligence, 83.9% less cost to run the AA benchmark, and 69.5% faster end-to-end.
Today's Pareto frontier
Against the frontier
- 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.
- gpt-oss-20b (High) is off the frontier: at the same or lower cost, GPT-6 Luna (Low) scores 21.50 for $10.6.
GPT-5.6 Luna (Xhigh)gpt-oss-20b (High)Today's Pareto frontierOpen-weights 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-xhigh/gpt-oss-20b · Markdown: /api/v1/compare/gpt-5-6-luna-xhigh/gpt-oss-20b?format=md · llms.txt · agent skill