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Solar Pro 4 vs Step 3.7 Flash

Solar Pro 4 and Step 3.7 Flash are closely matched at 35.2 and 30.2 on the LLM Stats Score. Step 3.7 Flash is 1.2x cheaper per token.

Upstage · StepFun · Updated for 2026

Which is better?

Solar Pro 4 and Step 3.7 Flash are closely matched on the overall LLM Stats Score at 35.2 and 30.2.

In the 1 individual benchmarks reported for both models, Step 3.7 Flash wins 1; this is a narrower head-to-head signal than the composite indexes.

On price, Step 3.7 Flash is roughly 1.2x cheaper per token on a blended 3:1 input/output basis, which adds up quickly at production volume.

Solar Pro 4 also accepts a larger context window (524,288 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 Solar Pro 4

  • you process long inputs — it offers a 524,288 token context window
  • you want the most recent training data — it shipped Aug 2026

Choose Step 3.7 Flash

  • you value its reported benchmark strengths — it wins 1 of 1 exact shared results
  • cost matters — it's about 1.2x 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
35.2
#87
30.2
#120
34.8
#83
30.2
#117
21.1
#90
19.9
#99
11.8
#107
13.5
#92
Cost, coverage & limits
Benchmark wins
0 of 1
1 of 1
Input price
$0.30 / M
$0.20 / M
Output price
$1.20 / M
$1.15 / M
Context window
524,288
262,144

Individual benchmarks

9 reported for Solar Pro 4 · 4 for Step 3.7 Flash

1 shared

Solar Pro 4 outperforms in 0 benchmarks, while Step 3.7 Flash is better at 1 benchmark (Terminal-Bench 2.1).

Step 3.7 Flash significantly outperforms across most benchmarks.

Sun Sep 20 2026 • llm-stats.com

Human preference

Blind head-to-head votes and playground preference scores

Pricing Analysis

Price comparison per million tokens

Step 3.7 Flash costs less

For input processing, Solar Pro 4 ($0.30/1M tokens) is 1.5x more expensive than Step 3.7 Flash ($0.20/1M tokens).

For output processing, Solar Pro 4 ($1.20/1M tokens) is 1.0x more expensive than Step 3.7 Flash ($1.15/1M tokens).

In conclusion, Solar Pro 4 is more expensive than Step 3.7 Flash.*

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

Lowest available price from all providers
Sun Sep 20 2026 • llm-stats.com
Upstage
Solar Pro 4
Input tokens$0.30
Output tokens$1.20
Best providerUnknown Organization
StepFun
Step 3.7 Flash
Input tokens$0.20
Output tokens$1.15
Best providerDeepinfra
Notice missing or incorrect data?Start an Issue

Context Window

Maximum input and output token capacity

Solar Pro 4 accepts 524,288 input tokens compared to Step 3.7 Flash's 262,144 tokens. Step 3.7 Flash can generate longer responses up to 262,144 tokens, while Solar Pro 4 is limited to 131,072 tokens.

Upstage
Solar Pro 4
Input524,288 tokens
Output131,072 tokens
StepFun
Step 3.7 Flash
Input262,144 tokens
Output262,144 tokens
Sun Sep 20 2026 • llm-stats.com

Input capabilities

Documented input modalities across available providers

Step 3.7 Flash supports multimodal inputs, whereas Solar Pro 4 does not.

Step 3.7 Flash can handle both text and other forms of data like images, making it suitable for multimodal applications.

Solar Pro 4

Text
Images
Audio
Video

Step 3.7 Flash

Text
Images
Audio
Video

License

Usage and distribution terms

Solar Pro 4 is licensed under a proprietary license, while Step 3.7 Flash uses Apache 2.0.

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

Solar Pro 4

Proprietary

Closed source

Step 3.7 Flash

Apache 2.0

Open weights

Release Timeline

When each model was launched

Solar Pro 4 was released on 2026-08-06, while Step 3.7 Flash was released on 2026-06-10.

Solar Pro 4 is 2 months newer than Step 3.7 Flash.

Solar Pro 4

Aug 6, 2026

1 months ago

1mo newer
Step 3.7 Flash

Jun 10, 2026

3 months ago

Knowledge Cutoff

When training data ends

Neither model specifies a knowledge cutoff date.

Unable to compare the recency of their training data.

No cutoff dates available

Provider Availability

Solar Pro 4 is available from Upstage. Step 3.7 Flash is available from DeepInfra.

Solar Pro 4

upstage logo
Unknown Organization
Input Price:Input: $0.30/1MOutput Price:Output: $1.20/1M

Step 3.7 Flash

deepinfra logo
Deepinfra
Input Price:Input: $0.20/1MOutput Price:Output: $1.15/1M
* 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 Solar Pro 4 and Step 3.7 Flash side-by-side, then vote on the output you prefer.

Solar Pro 4
✓ Preferred
Step 3.7 Flash
Open in Playground

FAQ

Common questions about Solar Pro 4 vs Step 3.7 Flash.

Which is better, Solar Pro 4 or Step 3.7 Flash?

Solar Pro 4 and Step 3.7 Flash are closely matched on the LLM Stats Score at 35.2 and 30.2. Solar Pro 4 is made by Upstage and Step 3.7 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 Solar Pro 4 compare to Step 3.7 Flash in benchmarks?

Solar Pro 4 scores AIME 2026: 95.3%, GPQA: 89.0%, LiveCodeBench: 87.8%, MMLU-Pro: 86.3%, AA-LCR: 71.0%. Step 3.7 Flash scores Terminal-Bench 2.1: 59.5%, SWE-Bench Pro: 56.3%, Humanity's Last Exam (with tools, text-only): 47.2%, GDPval: 45.8%.

Is Solar Pro 4 cheaper than Step 3.7 Flash?

Step 3.7 Flash is 1.5x cheaper for input tokens. Solar Pro 4 costs $0.30/M input and $1.20/M output via upstage. Step 3.7 Flash costs $0.20/M input and $1.15/M output via deepinfra.

What are the context window sizes for Solar Pro 4 and Step 3.7 Flash?

Solar Pro 4 supports 524K tokens and Step 3.7 Flash supports 262K tokens. A larger context window lets you process longer documents, conversations, or codebases in a single request.

What are the main differences between Solar Pro 4 and Step 3.7 Flash?

Key differences include LLM Stats Score (35.2 vs 30.2), context window (524K vs 262K), input pricing ($0.30 vs $0.20/M), multimodal support (no vs yes), licensing (Proprietary vs Apache 2.0). See the full comparison above for benchmark-by-benchmark results.

Who makes Solar Pro 4 and Step 3.7 Flash?

Solar Pro 4 is developed by Upstage and Step 3.7 Flash is developed by StepFun.