Claude Opus 5.5 (High, Default Fallback) vs gpt-oss-20b (High)
Which is better for the money: Claude Opus 5.5 (High, Default Fallback) by Anthropic 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
Claude Opus 5.5 (High, Default Fallback) scores 44.6 points higher (53.6 vs 9.0) but costs 75× as much to run the benchmark ($2172 vs $28.8; flagship vs budget cost classes). They are not alternatives at one budget: pick Claude Opus 5.5 (High, Default Fallback) when you need intelligence above 9.0, and gpt-oss-20b (High) when 9.0 is enough.
| Metric | Claude Opus 5.5 (High, Default Fallback) | gpt-oss-20b (High) | Difference |
|---|---|---|---|
| Intelligence (higher is better) | 53.6 | 9.0 | −83.2% gpt-oss-20b (High) is 83.2% less intelligent |
| Total AA cost (lower is better) | $2,172.43 | $28.81 | −98.7% gpt-oss-20b (High) is 98.7% cheaper |
| End-to-end time (lower is better) | 39.33s | 14.42s | −63.3% gpt-oss-20b (High) is 63.3% faster |
| Price per 1M tokens (in / out) | $4.00 / $20.0 | $0.05 / $0.22 | |
| Input modalities | Text, Image | Text |
gpt-oss-20b (High) vs Claude Opus 5.5 (High, Default Fallback): 83.2% less intelligence, 98.7% less cost to run the AA benchmark, and 63.3% faster end-to-end.
Today's Pareto frontier
Against the frontier
- Claude Opus 5.5 (High, Default Fallback) is on today's frontier: nothing is both smarter and cheaper.
- gpt-oss-20b (High) is off the frontier: at the same or lower cost, GPT-6 Luna (Low) scores 21.50 for $10.6.
Claude Opus 5.5 (High, Default Fallback)gpt-oss-20b (High)Today's Pareto frontierOpen-weights frontierEvery other model
Matchup
Compare something else
Agents:
Accept: text/markdown or ?format=md returns this page as Markdown. JSON: /api/v1/compare/claude-opus-5-5-high/gpt-oss-20b · Markdown: /api/v1/compare/claude-opus-5-5-high/gpt-oss-20b?format=md · llms.txt · agent skill