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GPT-6 Sol vs Step-3.5-Flash

GPT-6 Sol leads the LLM Stats Score 49.4 to 37.1. Step-3.5-Flash is 22.9x cheaper per token.

OpenAI · StepFun · Updated for 2026

Which is better?

GPT-6 Sol leads the overall LLM Stats Score 49.4 to 37.1, ranking #21 overall.

On price, Step-3.5-Flash is roughly 22.9x cheaper per token on a blended 3:1 input/output basis, which adds up quickly at production volume.

GPT-6 Sol also accepts a larger context window (1,050,000 input tokens), making it the stronger choice for long documents and large codebases.

Based on current LLM Stats indexes, shared benchmarks, pricing, and model metadata for 2026.

Choose GPT-6 Sol

  • overall performance matters — it scores 49.4 and ranks #21 on LLM Stats
  • your work emphasizes reasoning and coding — it leads those capability indexes
  • you process long inputs — it offers a 1,050,000 token context window
  • you want the most recent training data — it shipped Sep 2026

Choose Step-3.5-Flash

  • cost matters — it's about 22.9x cheaper per token
  • you need open weights you can self-host or fine-tune

At a glance

The differences that matter most.

Core performance indexes
49.4
#21
37.1
#74
45.6
#29
37.2
#73
35.8
#25
20.5
#102
36.7
#15
15.3
#90
Cost, coverage & limits
Benchmark wins
Input price
$2.00 / M
$0.10 / M
Output price
$10.00 / M
$0.40 / M
Context window
1,050,000
65,536

Capability indexes

Additional strengths measured across groups of related public benchmarks

1 shared
Index
GPT-6 Sol
Step-3.5-Flash
26.6#25
13.3#101
Conservative TrueSkill rating · higher is betterHow scores work

Individual benchmarks

5 reported for GPT-6 Sol · 7 for Step-3.5-Flash

No common benchmarks found

GPT-6 Sol and Step-3.5-Flashdon't have any common benchmark datasets to compare. They may have been evaluated on different testing suites.

Human preference

Blind head-to-head votes and playground preference scores

Pricing Analysis

Price comparison per million tokens

Step-3.5-Flash costs less

For input processing, GPT-6 Sol ($2.00/1M tokens) is 20.0x more expensive than Step-3.5-Flash ($0.10/1M tokens).

For output processing, GPT-6 Sol ($10.00/1M tokens) is 25.0x more expensive than Step-3.5-Flash ($0.40/1M tokens).

In conclusion, GPT-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
Wed Sep 23 2026 • llm-stats.com
OpenAI
GPT-6 Sol
Input tokens$2.00
Output tokens$10.00
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-6 Sol accepts 1,050,000 input tokens compared to Step-3.5-Flash's 65,536 tokens. GPT-6 Sol can generate longer responses up to 128,000 tokens, while Step-3.5-Flash is limited to 8,192 tokens.

OpenAI
GPT-6 Sol
Input1,050,000 tokens
Output128,000 tokens
StepFun
Step-3.5-Flash
Input65,536 tokens
Output8,192 tokens
Wed Sep 23 2026 • llm-stats.com

Input capabilities

Documented input modalities across available providers

GPT-6 Sol supports multimodal inputs, whereas Step-3.5-Flash does not.

GPT-6 Sol can handle both text and other forms of data like images, making it suitable for multimodal applications.

GPT-6 Sol

Text
Images
Audio
Video

Step-3.5-Flash

Text
Images
Audio
Video

License

Usage and distribution terms

GPT-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-6 Sol

Proprietary

Closed source

Step-3.5-Flash

Apache 2.0

Open weights

Release Timeline

When each model was launched

GPT-6 Sol was released on 2026-09-22, while Step-3.5-Flash was released on 2026-02-02.

GPT-6 Sol is 8 months newer than Step-3.5-Flash.

GPT-6 Sol

Sep 22, 2026

0 days ago

7mo newer
Step-3.5-Flash

Feb 2, 2026

7 months ago

Knowledge Cutoff

When training data ends

GPT-6 Sol has a documented knowledge cutoff of 2026-04-20, while Step-3.5-Flash's cutoff date is not specified.

We can confirm GPT-6 Sol's training data extends to 2026-04-20, but cannot make a direct comparison without Step-3.5-Flash's cutoff date.

GPT-6 Sol

Apr 2026

Step-3.5-Flash

Provider Availability

GPT-6 Sol is available from OpenAI. Step-3.5-Flash is available from StepFun.

GPT-6 Sol

openai logo
OpenAI
Input Price:Input: $2.00/1MOutput Price:Output: $10.00/1M

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

Judge for yourself.

Run your own prompts against GPT-6 Sol and Step-3.5-Flash side-by-side, then vote on the output you prefer.

GPT-6 Sol
✓ Preferred
Step-3.5-Flash
Open in Playground

FAQ

Common questions about GPT-6 Sol vs Step-3.5-Flash.

Which is better, GPT-6 Sol or Step-3.5-Flash?

GPT-6 Sol leads the LLM Stats Score 49.4 to 37.1. GPT-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 capability indexes, individual benchmarks, pricing, and limits above.

How does GPT-6 Sol compare to Step-3.5-Flash in benchmarks?

GPT-6 Sol scores DeepSWE 1.1: 68.8%, OSWorld 2.0: 64.4%, Agents' Last Exam: 56.4%, FrontierCode 1.1: 49.3%, AutomationBench v1.0.6: 33.2%. 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-6 Sol cheaper than Step-3.5-Flash?

Step-3.5-Flash is 20.0x cheaper for input tokens. GPT-6 Sol costs $2.00/M input and $10.00/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-6 Sol and Step-3.5-Flash?

GPT-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-6 Sol and Step-3.5-Flash?

Key differences include LLM Stats Score (49.4 vs 37.1), context window (1.1M vs 66K), input pricing ($2.00 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-6 Sol and Step-3.5-Flash?

GPT-6 Sol is developed by OpenAI and Step-3.5-Flash is developed by StepFun.