Model Comparison

GPT-5.4 vs Step-3.5-Flash

GPT-5.4 significantly outperforms across most benchmarks. Step-3.5-Flash is 32.1x cheaper per token.

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Performance Benchmarks

Comparative analysis across standard metrics

2 benchmarks

GPT-5.4 outperforms in 2 benchmarks (BrowseComp, Terminal-Bench 2.0), while Step-3.5-Flash is better at 0 benchmarks.

GPT-5.4 significantly outperforms across most benchmarks.

Mon Apr 20 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-5.4 ($2.50/1M tokens) is 25.0x more expensive than Step-3.5-Flash ($0.10/1M tokens).

For output processing, GPT-5.4 ($15.00/1M tokens) is 37.5x more expensive than Step-3.5-Flash ($0.40/1M tokens).

In conclusion, GPT-5.4 is more expensive than Step-3.5-Flash.*

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

Lowest available price from all providers
Mon Apr 20 2026 • llm-stats.com
OpenAI
GPT-5.4
Input tokens$2.50
Output tokens$15.00
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-5.4 accepts 1,000,000 input tokens compared to Step-3.5-Flash's 65,536 tokens. GPT-5.4 can generate longer responses up to 128,000 tokens, while Step-3.5-Flash is limited to 8,192 tokens.

OpenAI
GPT-5.4
Input1,000,000 tokens
Output128,000 tokens
StepFun
Step-3.5-Flash
Input65,536 tokens
Output8,192 tokens
Mon Apr 20 2026 • llm-stats.com

Input Capabilities

Supported data types and modalities

GPT-5.4 supports multimodal inputs, whereas Step-3.5-Flash does not.

GPT-5.4 can handle both text and other forms of data like images, making it suitable for multimodal applications.

GPT-5.4

Text
Images
Audio
Video

Step-3.5-Flash

Text
Images
Audio
Video

License

Usage and distribution terms

GPT-5.4 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-5.4

Proprietary

Closed source

Step-3.5-Flash

Apache 2.0

Open weights

Release Timeline

When each model was launched

GPT-5.4 was released on 2026-03-05, while Step-3.5-Flash was released on 2026-02-02.

GPT-5.4 is 1 month newer than Step-3.5-Flash.

GPT-5.4

Mar 5, 2026

1 months ago

1mo newer
Step-3.5-Flash

Feb 2, 2026

2 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

GPT-5.4 is available from OpenAI. Step-3.5-Flash is available from StepFun.

GPT-5.4

openai logo
OpenAI
Input Price:Input: $2.50/1MOutput Price:Output: $15.00/1M

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

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Key Takeaways

OpenAI
Larger context window (1,000,000 tokens)
Supports multimodal inputs
Higher BrowseComp score (82.7% vs 69.0%)
Higher Terminal-Bench 2.0 score (75.1% vs 51.0%)
StepFun
Less expensive input tokens
Less expensive output tokens
Has open weights

Detailed Comparison

AI Model Comparison Table
Feature
OpenAI
GPT-5.4
StepFun
Step-3.5-Flash

FAQ

Common questions about GPT-5.4 vs Step-3.5-Flash

GPT-5.4 significantly outperforms across most benchmarks. GPT-5.4 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.
GPT-5.4 scores Tau2 Telecom: 98.9%, ARC-AGI: 93.7%, Graphwalks BFS <128k: 93.0%, GPQA: 92.8%, Graphwalks parents <128k: 89.8%. 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%.
Step-3.5-Flash is 25.0x cheaper for input tokens. GPT-5.4 costs $2.50/M input and $15.00/M output via openai. Step-3.5-Flash costs $0.10/M input and $0.40/M output via stepfun.
GPT-5.4 supports 1.0M 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.
Key differences include context window (1.0M vs 66K), input pricing ($2.50 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.
GPT-5.4 is developed by OpenAI and Step-3.5-Flash is developed by StepFun.