Mercury 2.5 vs Step 5 Preview
Which is better for the money: Mercury 2.5 by Inception 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 31.4 points higher (43.7 vs 12.3) but costs 5.5× as much to run the benchmark ($1190 vs $218; premium vs mid-range cost classes). They are not alternatives at one budget: pick Step 5 Preview when you need intelligence above 12.3, and Mercury 2.5 when 12.3 is enough.
| Metric | Mercury 2.5 | Step 5 Preview | Difference |
|---|---|---|---|
| Intelligence (higher is better) | 12.3 | 43.7 | +255.3% Step 5 Preview is 3.6× more intelligent |
| Total AA cost (lower is better) | $218.11 | $1,190.26 | +445.7% Step 5 Preview is 5.5× more expensive |
| End-to-end time (lower is better) | 4.33s | 12.08s | +179.0% Step 5 Preview is 179.0% slower |
| Price per 1M tokens (in / out) | $0.25 / $0.75 | $1.00 / $2.70 | |
| Input modalities | Text | Text, Image |
Step 5 Preview vs Mercury 2.5: 255.3% more intelligence, 445.7% more cost to run the AA benchmark, and 179.0% slower end-to-end.
Today's Pareto frontier
Against the frontier
- Mercury 2.5 is off the frontier: at the same or lower cost, MiMo-V2.6-Pro scores 46.30 for $207.
- Step 5 Preview is off the frontier: at the same or lower cost, GPT-6.1 Sol (Max) scores 51.80 for $1082.
Mercury 2.5Step 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/mercury-2-5/step-5 · Markdown: /api/v1/compare/mercury-2-5/step-5?format=md · llms.txt · agent skill