Model Comparison

GPT-5.6 Sol vs Step-3.5-FlashWhich is better in 2026?

GPT-5.6 Sol significantly outperforms across most benchmarks. Step-3.5-Flash is 64.3x cheaper per token.

Verdict: GPT-5.6 Sol vs Step-3.5-Flash — which is better?

GPT-5.6 Sol (by OpenAI) and Step-3.5-Flash (by StepFun) are two of the AI models people compare most. Here is how they stack up on benchmarks, price and capabilities, and which one to pick in 2026.

GPT-5.6 Sol outperforms in 1 benchmarks (BrowseComp), while Step-3.5-Flash is better at 0 benchmarks. GPT-5.6 Sol significantly outperforms across most benchmarks.

On price, Step-3.5-Flash is roughly 64.3x cheaper per token on a blended 3:1 input/output basis, which adds up quickly at production volume.

GPT-5.6 Sol also accepts a larger context window (1,050,000 input tokens), making it the stronger choice for long documents and large codebases.

Choose GPT-5.6 Sol if…

  • you want the strongest raw capability — it leads on 1 of 1 shared benchmarks
  • you process long inputs — it offers a 1,050,000 token context window
  • you want the most recent training data — it shipped Jul 2026

Choose Step-3.5-Flash if…

  • cost matters — it's about 64.3x cheaper per token
  • you need open weights you can self-host or fine-tune

Performance Benchmarks

Comparative analysis across standard metrics

1 benchmarks

GPT-5.6 Sol outperforms in 1 benchmarks (BrowseComp), while Step-3.5-Flash is better at 0 benchmarks.

GPT-5.6 Sol significantly outperforms across most benchmarks.

Tue Jul 21 2026 • llm-stats.com

Arena Performance

Human preference votes

Pricing Analysis

Price comparison per million tokens

Step-3.5-Flash costs less

For input processing, GPT-5.6 Sol ($5.00/1M tokens) is 50.0x more expensive than Step-3.5-Flash ($0.10/1M tokens).

For output processing, GPT-5.6 Sol ($30.00/1M tokens) is 75.0x more expensive than Step-3.5-Flash ($0.40/1M tokens).

In conclusion, GPT-5.6 Sol is more expensive than Step-3.5-Flash.*

* Using a 3:1 ratio of input to output tokens

Lowest available price from all providers
Tue Jul 21 2026 • llm-stats.com
OpenAI
GPT-5.6 Sol
Input tokens$5.00
Output tokens$30.00
Best providerOpenAI
StepFun
Step-3.5-Flash
Input tokens$0.10
Output tokens$0.40
Best providerStepFun
Notice missing or incorrect data?Start an Issue→

Context Window

Maximum input and output token capacity

GPT-5.6 Sol accepts 1,050,000 input tokens compared to Step-3.5-Flash's 65,536 tokens. GPT-5.6 Sol can generate longer responses up to 128,000 tokens, while Step-3.5-Flash is limited to 8,192 tokens.

OpenAI
GPT-5.6 Sol
Input1,050,000 tokens
Output128,000 tokens
StepFun
Step-3.5-Flash
Input65,536 tokens
Output8,192 tokens
Tue Jul 21 2026 • llm-stats.com

Input Capabilities

Supported data types and modalities

GPT-5.6 Sol supports multimodal inputs, whereas Step-3.5-Flash does not.

GPT-5.6 Sol can handle both text and other forms of data like images, making it suitable for multimodal applications.

GPT-5.6 Sol

Text
Images
Audio
Video

Step-3.5-Flash

Text
Images
Audio
Video

License

Usage and distribution terms

GPT-5.6 Sol is licensed under a proprietary license, while Step-3.5-Flash uses Apache 2.0.

License differences may affect how you can use these models in commercial or open-source projects.

GPT-5.6 Sol

Proprietary

Closed source

Step-3.5-Flash

Apache 2.0

Open weights

Release Timeline

When each model was launched

GPT-5.6 Sol was released on 2026-07-09, while Step-3.5-Flash was released on 2026-02-02.

GPT-5.6 Sol is 5 months newer than Step-3.5-Flash.

GPT-5.6 Sol

Jul 9, 2026

1 weeks ago

5mo newer
Step-3.5-Flash

Feb 2, 2026

5 months ago

Knowledge Cutoff

When training data ends

GPT-5.6 Sol has a documented knowledge cutoff of 2026-02-16, while Step-3.5-Flash's cutoff date is not specified.

We can confirm GPT-5.6 Sol's training data extends to 2026-02-16, but cannot make a direct comparison without Step-3.5-Flash's cutoff date.

GPT-5.6 Sol

Feb 2026

Step-3.5-Flash

—

Provider Availability

GPT-5.6 Sol is available from OpenAI. Step-3.5-Flash is available from StepFun.

GPT-5.6 Sol

openai logo
OpenAI
Input Price:Input: $5.00/1MOutput Price:Output: $30.00/1M

Step-3.5-Flash

stepfun logo
StepFun
Input Price:Input: $0.10/1MOutput Price:Output: $0.40/1M
* Prices shown are per million tokens

Outputs Comparison

Notice missing or incorrect data?Start an Issue discussion→

Key Takeaways

OpenAI
Larger context window (1,050,000 tokens)
Supports multimodal inputs
Higher BrowseComp score (90.4% vs 69.0%)
StepFun
Less expensive input tokens
Less expensive output tokens
Has open weights

Detailed Comparison

Interactive Arena

Judge for yourself.

Run your own prompts against GPT-5.6 Sol and Step-3.5-Flash side-by-side, then vote on the output you prefer.

GPT-5.6 Sol
✓ Preferred
Step-3.5-Flash
Open in Playground
AI Model Comparison Table
Feature
OpenAI
GPT-5.6 Sol
StepFun
Step-3.5-Flash

FAQ

Common questions about GPT-5.6 Sol vs Step-3.5-Flash.

Which is better, GPT-5.6 Sol or Step-3.5-Flash?

GPT-5.6 Sol significantly outperforms across most benchmarks. GPT-5.6 Sol is made by OpenAI and Step-3.5-Flash is made by StepFun. The best choice depends on your use case — compare their benchmark scores, pricing, and capabilities above.

How does GPT-5.6 Sol compare to Step-3.5-Flash in benchmarks?

GPT-5.6 Sol scores Connectors: 100.0%, Capture-the-Flag Challenges (Internal): 96.7%, HealthBench Consensus: 95.5%, GPQA: 94.6%, MRCR v2 (8-needle): 91.5%. Step-3.5-Flash scores AIME 2025: 97.3%, Tau-bench: 88.2%, LiveCodeBench v6: 86.4%, IMO-AnswerBench: 85.4%, SWE-Bench Verified: 74.4%.

Is GPT-5.6 Sol cheaper than Step-3.5-Flash?

Step-3.5-Flash is 50.0x cheaper for input tokens. GPT-5.6 Sol costs $5.00/M input and $30.00/M output via openai. Step-3.5-Flash costs $0.10/M input and $0.40/M output via stepfun.

What are the context window sizes for GPT-5.6 Sol and Step-3.5-Flash?

GPT-5.6 Sol supports 1.1M tokens and Step-3.5-Flash supports 66K tokens. A larger context window lets you process longer documents, conversations, or codebases in a single request.

What are the main differences between GPT-5.6 Sol and Step-3.5-Flash?

Key differences include context window (1.1M vs 66K), input pricing ($5.00 vs $0.10/M), multimodal support (yes vs no), licensing (Proprietary vs Apache 2.0). See the full comparison above for benchmark-by-benchmark results.

Who makes GPT-5.6 Sol and Step-3.5-Flash?

GPT-5.6 Sol is developed by OpenAI and Step-3.5-Flash is developed by StepFun.

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