GPT-5.5 Instant (June 2026) vs Step 5 Preview
Which is better for the money: GPT-5.5 Instant (June 2026) 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 17.7 points higher (43.7 vs 26.0) but costs 1.0× as much to run the benchmark ($1190 vs $1184; both premium class). Pick Step 5 Preview when the extra intelligence is worth the premium, otherwise GPT-5.5 Instant (June 2026).
| Metric | GPT-5.5 Instant (June 2026) | Step 5 Preview | Difference |
|---|---|---|---|
| Intelligence (higher is better) | 26.0 | 43.7 | +68.1% Step 5 Preview is 68.1% more intelligent |
| Total AA cost (lower is better) | $1,184.34 | $1,190.26 | +0.5% Step 5 Preview is 0.5% more expensive |
| End-to-end time (lower is better) | 17.49s | 12.32s | −29.6% Step 5 Preview is 29.6% faster |
| Price per 1M tokens (in / out) | $5.00 / $30.0 | $1.00 / $2.70 | |
| Input modalities | Text, Image | Text, Image |
Step 5 Preview vs GPT-5.5 Instant (June 2026): 68.1% more intelligence, 0.5% more cost to run the AA benchmark, and 29.6% faster end-to-end.
Today's Pareto frontier
Against the frontier
- GPT-5.5 Instant (June 2026) is off the frontier: at the same or lower cost, GPT-6.1 Sol (Max) scores 51.80 for $1082.
- Step 5 Preview is off the frontier: at the same or lower cost, GPT-6.1 Sol (Max) scores 51.80 for $1082.
GPT-5.5 Instant (June 2026)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-5-5-instant-06-26/step-5 · Markdown: /api/v1/compare/gpt-5-5-instant-06-26/step-5?format=md · llms.txt · agent skill