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GPT-5 vs Step-3.5-Flash
Comprehensive side-by-side LLM comparison
Both models show comparable benchmark performance. GPT-5 supports multimodal inputs. Both models have their strengths depending on your specific coding needs.
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OpenAI
GPT-5, released by OpenAI on August 7, 2025, is a large language model that combines direct generation and extended reasoning in a single unified system with a built-in routing mechanism. It features a 400K token context window, 128K maximum output tokens, native multimodal support (text, image, audio, video), and demonstrated strong results across coding, mathematics, visual understanding, and health benchmarks at release. GPT-5 targets complex multi-step tasks including advanced coding, mathematical problem solving, and long-context analysis.
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StepFun
Step-3.5-Flash, released by StepFun on February 2, 2026, is a Mixture-of-Experts large language model with 197 billion total parameters and approximately 11 billion active parameters per inference. It features a 256K token context window using a 3:1 sliding-window-to-full-attention ratio, processing 100–350 tokens per second. Step-3.5-Flash targets agentic tasks, coding workflows, and open-source deployments requiring frontier reasoning capabilities with efficient inference, under an Apache 2.0 license.
5 months newer
GPT-5
OpenAI
2025-08-07
Step-3.5-Flash
StepFun
2026-02-02
Performance Metrics
Context window and performance specifications
Average performance across 1 common benchmarks
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GPT-5
Average Score:74.9%(+0.5%)
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Step-3.5-Flash
Average Score:74.4%
Performance comparison across key benchmark categories
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GPT-5
Coding74.9%(+0.5%)
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Step-3.5-Flash
Coding74.4%
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Knowledge Cutoff
Training data recency comparison
GPT-5
2025-05
More recent knowledge cutoff means awareness of newer technologies and frameworks
Provider Availability & Performance
Available providers and their performance metrics
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GPT-5
1 providers
OpenAI
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Step-3.5-Flash
0 providers
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GPT-5
Avg Score:74.9%(+0.5%)
Providers:1
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Step-3.5-Flash
Avg Score:74.4%
Providers:0