Riverflow V2 Fast vs 
Step 5 Preview
Step 5 Preview has a larger context window than Riverflow V2 Fast (1.0M tokens vs 8K tokens).
Written rounds
2 promptsBuy-side IC memo on a fictional SaaS company. Valuation, then the diligence questions.
Five-year LBO on a fictional HVAC business. Returns first, then the sensitivities.
Price and specs
Not enough votes to call it. On the specs, Step 5 Preview has the edge: bigger model tier, newer, bigger context window.
| Spec | Riverflow V2 Fast | Step 5 Preview |
|---|---|---|
| Input price | — | $1/M tokens |
| Output price | — | $2.7/M tokens |
| Context window | 8K tokens | 1.0M tokens |
| Free API (OpenRouter) | No | No |
| Released | Feb 2026 | Oct 2026 |
| At 10M a month | not listed | $10.00 |
Input tokens at list price. No caching, no batch discount.
Where to run it
Riverflow V2 Fast1 host
Step 5 Preview1 host
Per million tokens. Prices and uptime via OpenRouter, checked 10 Oct 2026.
Common questions
What is the difference between Riverflow V2 Fast and Step 5 Preview?
Riverflow V2 Fast is developed by Sourceful while Step 5 Preview is developed by StepFun. Riverflow V2 Fast has a 8K token context window vs Step 5 Preview's 1.0M. You can compare their actual outputs across 2 challenges on Rival to see how they differ in practice.
Which is better, Riverflow V2 Fast or Step 5 Preview?
It depends on your use case. Riverflow V2 Fast and Step 5 Preview each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 2 challenges so you can judge which fits your needs best.
How can I compare Riverflow V2 Fast and Step 5 Preview on Rival?
This page shows a side-by-side comparison of Riverflow V2 Fast and Step 5 Preview across shared challenges. You can vote on which model produced the better output in a blind duel. Browsing and voting are free. No account is needed to look; signing in only saves your votes and likes.
More comparisons
Against the newest arrivals
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- Riverflow V2 Fast vs Mistral Large 4Landed Oct 2026
- Step 5 Preview vs GPT-6.1 SolLanded Sep 2026
- Riverflow V2 Fast vs Claude Sonnet 5.5Landed Sep 2026
- Step 5 Preview vs Solar Mini 4Landed Sep 2026
- Riverflow V2 Fast vs Qwen3.8 Max PrimeLanded Sep 2026
- Step 5 Preview vs GLM 5.3 PrimeLanded Sep 2026
Same lab, same size, long tail
- Riverflow V2 Fast vs Ox AlphaSame size
- Riverflow V2 Fast vs GPT-6.1 SolSame size
- Step 5 Preview vs Mistral Large 4Same size
- Step 5 Preview vs Hy3Same size
- Riverflow V2 Fast vs GPT-5.6 LunaNew provider
- Riverflow V2 Fast vs GPT-5.6 Luna ProNew provider
- Riverflow V2 Fast vs GPT-5.6 SolNew provider
- Riverflow V2 Fast vs GPT-5.6 TerraSame size
