GPT-5.6 Luna (Low) vs Step 5 Preview
Which is better for the money: GPT-5.6 Luna (Low) by OpenAI or Step 5 Preview by StepFun? Intelligence, total benchmark cost, and end-to-end time from Artificial Analysis & other sources, snapshot 2026-10-25.
Trade-off
Verdict
Depends on your budget
Step 5 Preview scores 22.7 points higher (43.7 vs 21.0) but costs 44× as much to run the benchmark ($1190 vs $27.0; premium vs budget cost classes). They are not alternatives at one budget: pick Step 5 Preview when you need intelligence above 21.0, and GPT-5.6 Luna (Low) when 21.0 is enough.
| Metric | GPT-5.6 Luna (Low) | Step 5 Preview | Difference |
|---|---|---|---|
| Intelligence (higher is better) | 21.0 | 43.7 | +108.1% Step 5 Preview is 2.1× more intelligent |
| Total AA cost (lower is better) | $27.02 | $1,190.26 | +4305.1% Step 5 Preview is 44× more expensive |
| End-to-end time (lower is better) | 5.90s | 12.32s | +108.8% Step 5 Preview is 108.8% slower |
| Price per 1M tokens (in / out) | $0.20 / $1.20 | $1.00 / $2.70 | |
| Input modalities | Text, Image | Text, Image |
Step 5 Preview vs GPT-5.6 Luna (Low): 108.1% more intelligence, 4305.1% more cost to run the AA benchmark, and 108.8% 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.
- Step 5 Preview 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)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-5-6-luna-low/step-5 · Markdown: /api/v1/compare/gpt-5-6-luna-low/step-5?format=md · llms.txt · agent skill