GPT-6 Luna (Medium) vs Step 5 Preview
Which is better for the money: GPT-6 Luna (Medium) by OpenAI or Step 5 Preview by StepFun? Intelligence, total benchmark cost, and end-to-end time from Artificial Analysis & other sources, snapshot 2026-10-24.
Trade-off
Verdict
Depends on your budget
Step 5 Preview scores 13.8 points higher (43.7 vs 29.9) but costs 38× as much to run the benchmark ($1190 vs $31.2; premium vs budget cost classes). They are not alternatives at one budget: pick Step 5 Preview when you need intelligence above 29.9, and GPT-6 Luna (Medium) when 29.9 is enough.
| Metric | GPT-6 Luna (Medium) | Step 5 Preview | Difference |
|---|---|---|---|
| Intelligence (higher is better) | 29.9 | 43.7 | +46.2% Step 5 Preview is 46.2% more intelligent |
| Total AA cost (lower is better) | $31.17 | $1,190.26 | +3718.6% Step 5 Preview is 38× more expensive |
| End-to-end time (lower is better) | 8.25s | 12.06s | +46.2% Step 5 Preview is 46.2% slower |
| Price per 1M tokens (in / out) | $0.10 / $0.50 | $1.00 / $2.70 | |
| Input modalities | Text, Image | Text, Image |
Step 5 Preview vs GPT-6 Luna (Medium): 46.2% more intelligence, 3718.6% more cost to run the AA benchmark, and 46.2% slower end-to-end.
Today's Pareto frontier
Against the frontier
- GPT-6 Luna (Medium) is on today's frontier: nothing is both smarter and cheaper.
- Step 5 Preview is off the frontier: at the same or lower cost, GPT-6.1 Sol (Max) scores 51.80 for $1082.
GPT-6 Luna (Medium)Step 5 PreviewToday'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-6-luna-medium/step-5 · Markdown: /api/v1/compare/gpt-6-luna-medium/step-5?format=md · llms.txt · agent skill