AI Models · Open-Source vs Paid

Step 5 Preview Open vs Gemini 3.1 Pro Preview Paid

Step 5 Preview vs Gemini 3.1 Pro Preview compared — price per token, context window, multimodality, openness and which to choose. Can the open-source model replace the paid one? Full 2026 breakdown.

Prices & specs refreshed from live data · olud.ai

Open-model prices = cheapest provider via OpenRouter; official maker rates may be higher.

Step 5 PreviewOpenStepfun
$1 /M input
$2.7 /M outputNo per-token fees if you self-host
TypeOpen-weight
Context window1M tokens
MultimodalYes
Self-hostYes
Gemini 3.1 Pro PreviewPaidGoogle
$2 /M input
$12 /M outputManaged API (no infra to run)
TypeProprietary
Context window1M tokens
MultimodalYes
Self-hostNo
Choose Step 5 Preview if you want to self-host, keep your data private and skip per-token fees — it's open-weight and runs on your own hardware. Choose Gemini 3.1 Pro Preview if you want frontier capability through a managed API with zero infrastructure to run.

Step 5 Preview vs Gemini 3.1 Pro Preview specs

SpecStep 5 PreviewGemini 3.1 Pro PreviewWinner
MakerStepfunGoogle–
TypeOpen-weightProprietaryStep 5 Preview
Context window1M tokens1M tokens= Tie
Input price$1/M · free self-host$2/MStep 5 Preview
Output price$2.7/M · free self-host$12/MStep 5 Preview
Vision / multimodalYesYes= Tie
Tool / function callingYesYes= Tie
Self-hostableYesNo (API only)Step 5 Preview
LicenseOpen weightsProprietaryStep 5 Preview

Price gap & when to choose each

4.4×cheaper per output token

Step 5 Preview is ~4.4× cheaper than Gemini 3.1 Pro Preview on output tokens ($2.7 vs $12 per M tokens).

Choose Step 5 Preview if…
  • You want to self-host or run on your cloud
  • You prioritize data privacy & control
  • You want the lowest operating costs
  • You are building open or reproducible AI
Choose Gemini 3.1 Pro Preview if…
  • You want frontier performance through a managed API
  • You value reliability & ecosystem
  • You don't want to manage infrastructure

Feature comparison

CapabilityStep 5 PreviewGemini 3.1 Pro Preview
Open weights (downloadable)✓✗
Self-hostable✓✗
Runs fully offline✓✗
Vision / multimodal✓✓
Tool / function calling✓✓
1M+ context window✓✓

Benchmarks: Step 5 Preview vs Gemini 3.1 Pro Preview

Independent benchmark scores measured by Artificial Analysis. Higher is better (except latency).

Step 5 Preview delivers 4.7× more intelligence per dollar.
Step 5 Preview
Gemini 3.1 Pro Preview
Intelligence index
43.7
29.7
Humanity's Last Exam
46.5%
47%
Long Context Reasoning
88.3%
82%
SciCode
58.9%
58.7%
Coding index
–
68.8
GPQA
–
94.1%
IFBench
–
77.1%
τ²-Bench
–
95.6%
τ-Bench Banking
–
21.4%
Terminal-Bench
–
73.8%
Terminal-Bench Hard
–
53.8%
Speed
201.5 tok/s
135.7 tok/s
Latency
0.87s
16.61s
Intelligence per $
30.7
6.6

Benchmark data by Artificial Analysis.

How Step 5 Preview and Gemini 3.1 Pro Preview score

🏆 Best value & openness: Step 5 Preview (4.9 vs 3.2 / 5)
CriterionStep 5 PreviewGemini 3.1 Pro Preview
Cost-efficiency4.53.5
Context window5.05.0
Openness5.01.5
Self-hosting5.01.0
Multimodality5.05.0

Scores come from live data — output price (cost), context length, open vs closed weights (openness & self-hosting) and vision/tool support (multimodality). Raw task quality isn't scored here; it depends on your benchmark — see the verdict.

What each model is

Step 5 Preview Open

Stepfun · Open-weight

Step 5 Preview is StepFun's flagship model for agentic work, built on a sparse Mixture-of-Experts architecture (27B active / 600B total parameters). It performs strongly in software engineering and professional...

Gemini 3.1 Pro Preview Paid

Google · Proprietary

Gemini 3.1 Pro Preview is Google’s frontier reasoning model, delivering enhanced software engineering performance, improved agentic reliability, and more efficient token usage across complex workflows. Building on the multimodal foundation.

Other models in these families

These variants are tracked but not compared here — one page per family keeps the comparison readable.

Other variants tracked
Step 3.7 FlashStep 3.5 Flash
Other variants tracked
Gemini 3.1 Pro Preview (batch)Gemini 2.5 ProNano Banana Pro (Gemini 3 Pro Image)Gemini 3.1 Pro Preview Custom Tools

Frequently asked questions

Is Step 5 Preview as good as Gemini 3.1 Pro Preview?

Step 5 Preview is open-weight and competitive on many tasks, but Gemini 3.1 Pro Preview may still lead on the hardest reasoning and agentic work. The gap keeps narrowing — benchmark both on your actual use case before deciding.

Can I run Step 5 Preview locally?

Yes. Step 5 Preview has open weights, so you can self-host it on your own GPUs or run it via a low-cost API. Gemini 3.1 Pro Preview is API-only and cannot be self-hosted.

How much cheaper is Step 5 Preview?

Step 5 Preview costs $2.7/M output vs $12/M for Gemini 3.1 Pro Preview — roughly 4x cheaper via API, and free if you self-host.

Step 5 Preview vs Gemini 3.1 Pro Preview — which should I pick in 2026?

Choose Step 5 Preview if you want to self-host, keep your data private and skip per-token fees — it's open-weight and runs on your own hardware. Choose Gemini 3.1 Pro Preview if you want frontier capability through a managed API with zero infrastructure to run.

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